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  • 1. 8 Infectious Diseases of the Skin Andrew F. Alexis, MD, MPH C o n t e n t s 8.1 Bacterial Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 8.2 Viral Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 8.3 Mycobacterial Infections . . . . . . . . . . . . . . . . . . . . . . . . . . 299 8.4 Sexually Transmitted Diseases . . . . . . . . . . . . . . . . . . . . 302 8.5 Nonvenereal Trepanomatoses . . . . . . . . . . . . . . . . . . . . 305 8.6 Parasitic Infections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 8.7 Rickettsial Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 Infectious Diseases of the Skin  287
  • 2. Committed to Your Future For practice exam questions and interactive study tools, visit the Dermatology In-Review Online Practice Exam and Study System at by
  • 3. 8.1 BACTERIAL INFECTIONSActinomycosis • Causative organism: Actinomyces israelii (an anaerobic gram-positive rod) • Characteristic features: Chronic suppurative nodules and sinus tracts with an exudate containing “sulfur granules” •  ost commonly involves the cervicofacial region, especially near mandible – “lumpy jaw.” M (Can also involve the abdomen and thoracic region) • Source of infection is “endogenous,” e.g., oral flora • Risk factors: Poor oral hygiene, penetrating foreign bodies, and dental proceduresActinomycetoma • Causative organisms: Aerobic filamentous bacteria including Nocardia brasilensis, Actinomadura madurae, A. pelletieri, and Streptomyces somaliensis • Characteristic features: Chronic, slowly progressive subcutaneous infection characterized by tumefaction, draining sinuses, and an exudate containing grains • Most commonly involves the foot • Source of infection is “exogenous,” e.g., soilAnthrax • Causative organism: Bacillus anthracis, a gram-positive spore-forming rod • Primarily caused by contact with infected wild or domestic animals, or their products (e.g., wool, goat, animal hides, bones, etc.) • B. anthracis has two exotoxins: edema toxin and lethal toxin, each comprised of a pair of noncovalently linked proteins u TIP – Edema toxin = Edema Factor (EF) + Protective Antigen (PA) a . anthracis has two exotoxins: B – Lethal toxin = Lethal Factor (LF) + PA edema toxin and lethal toxin – EF causes gelatinous edema of anthrax skin lesions by inducing an increase in cyclic adenosine monophosphate (cAMP) levels – LF causes shock and death in disseminated anthrax via the release of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) – PA is responsible for entry of exotoxins into the cell by receptor-mediated endocytosis. Therefore antibodies to PA will prevent the actions of EF and LF • Three clinical forms: Inhalational, Gastrointestinal, and Cutaneous • Treatment: u TIP 1.) Bioterrorism associated: Ciprofloxacin or Doxycycline a rimary lesion is a “malignant P 2.) Conventional anthrax: Penicillin pustule,” which begins as a painless papule, evolves into a hemorrhagicBartonellosis bulla with surrounding nonpitting edema, and ultimately forms a • Infections caused by aerobic, gram-negative bacilli of the characteristic black eschar genus Bartonella • Multiple different species produce a variety of cutaneous diseases (see Table 8-1) Infectious Diseases of the Skin  289
  • 4. Table 8-1. Cutaneous Diseases Bartonella Species Vector Treament Cat flea-Ctenocephali- des felis (transmission Spontaneous resolution Cat-Scratch Disease B. henselae from cat to cat only); in the majority of cases humans infected by cat bite or scratch B. henselae Erythromycin Bacillary Angiomatosis Unknown B. quintana Doxycycline Human body louse - Doxycycline Trench Fever B. quintana Pediculus humanus Erythromycin corporis Chloramphenicol Oroya Fever (Carrions Sandfly - Lutzomyia (because of frequent Disease) Verruga B. bacilliformis verrucarum superinfection with Peruana Salmonella)Borreliosis Table 8-2. Borreliosis Relapsing Fever Relapsing Fever - Louse-Borne - Tick-Borne Lyme Disease (Africa, South (Western United America) States) B. duttonii Borrelia Species B. burgdorferi B. recurrentis B. hermsii Ixodes dammini* (Northeast U.S.) Ixodes pacificus Human body louse Soft-bodied ticks Vector (Western U.S.) (Pediculus humanus) (Ornithodoros) Ixodes ricinus (Europe) • Paroxysmal fevers (2 episodes) • Headache • Erythema Migrans • Lymphocytoma Clinical Features • Acrodermatitis • Mylagias • Same as louse-borne Chronica Atrophicans • Erythematous or petechial macules on trunk, and extremities  Doxycycline 100 mg po bid for 14-21 days Doxycycline 100 mg po Doxycycline 100 mg po Treatment (Pregnancy, Children x 1 dose bid for 7 days 9: Amoxicillin) *Ixodes dammini = Ixodes scapularis290    2011/2012 Dermatology In-Review l Committed to Your Future
  • 5. Botryomycosis • Causative organisms: S. aureus, P. aeruginosa, E. coli, and Proteus species • Characteristic features: Chronic or subacute suppurative nodules or plaques • Granular bodies on light microscopy • Risk Factors: Immunosuppression (e.g., HIV), diabetes, trauma, alcoholism • Treatment: Dependent on causative organismEcthyma Gangrenosum • Causative organism: Pseudomonas aeruginosa septicemia • Characteristic features: “Gunmetal gray,” infarcts with surrounding erythema • Treatment: Intravenous antipseudomonal antibioticsErysipeloid • Causative organism: Erysipelothrix rhusiopathiae – a gram-positive rod • Typically occurs in handlers of contaminated raw fish or meat (e.g., fishermen, butchers) • Characteristic features: A tender, well-demarcated, violaceous lesion with raised margins and central clearing, typically on the hand or finger • Treatment: PenicillinGlanders • Causative organism: Burkholderia mallei • Disease caused by contact with infected horses • Characteristic features: Ulcerated nodule with regional lymphadenopathy • Treatment: Imipenem or doxycyclineMeningococcemia • Causative organism: Neisseria meningitides (a gram-negative diplococcus) • Affects young children and patients with complement deficiencies • Characteristic features: Petechiae that often progress to large ecchymotic or necrotic areas on trunk and extremities; fever, chills, meningitis, hypotension • Treatment: IV-Penicillin or ceftriaxonePitted Keratolysis • Causative organism: Micrococcus sedentarius • Characteristic features: Shallow 1-3 mm pits on plantar surface of feet • Treatment: Topical erythromycin, clindamycin, or benzoyl peroxideRat-bite Fever (Haverhill Fever) • Causative organism: Streptobacillus moniliformis • Infection acquired from rodents or contaminated food • Characteristic features: Fever, arthralgias, rash (nonspecific erythematous macules or papules, which can become generalized) • Treatment: PenicillinRhinoscleroma • Causative organism: Klebsiella pneumoniae rhinoscleromatis • Characteristic features: Hypertrophic plaques on external nares • Mikulicz cells on histopathology • Treatment: Ciprofloxacin Infectious Diseases of the Skin  291
  • 6. Staphyloccocal Infections Phage group II S. aureus produce various exotoxins, which can produce bullous or exfolia-tive skin lesions and syndromes. Table 8-3. Bullous or Exfoliative Skin Lesions and Syndromes Scarlatiniform EruptionToxic Shock Syndrome Staphylococcal Scalded Bullous Impetigo (Staphylococcal Scarlet(TSS) Skin Syndrome Fever) • nterotoxins B and C E • Exfoliative • xfoliative toxins A E • eneralized G (50% of nonmenstrual toxins/Epidermolytic and B ­scarlatiniform rash cases) toxins A and B (ET-A, • taphylococcal S • o other signs N • SST-1 (TSS toxin 1) – T ET-B) bind to desmo- infection at site of of Scarlet Fever menstrual cases1 glein-1 lesion (e.g., Pastia’s • ever, hypotension, F • hildren under 5 C • ubcorneal blister S lines, pharyngitis, generalized years of age, adults • TSST-1 strawberry tongue) scarlatiniform with renal failure or eruption followed by immunodeficiency desquamation • istant (extra- D lesional) site of staphylococcal infection • ositive Nikolsky’s P sign in lesional and non-lesional skin* • ubgranular blister S *Unlike Toxic Epidermal Necrolysis, in which Nikolsky’s sign is positive in lesional skin onlyOther Staphylococcal Infections • Impetigo (non-bullous) • Folliculitis/Furunculosis • Sycosis barbae • Ecthyma (uncommonly; majority of cases caused by Group A streptococcus) • Cellulitis • Botryomycosis (see description above) • Acute paronychia • Felon (staphylococcal whitlow) • Purpura fulminans • EndocarditisStreptococcal Infections Diseases Caused by Group A β-hemolytic streptococcus Blistering Distal Dactylitis • Tense blisters filled with purulent fluid and surrounding erythema on the dorsal surface of distal fingers and toes292    2011/2012 Dermatology In-Review l Committed to Your Future
  • 7. Perianal streptococcal “cellulitis” • Sharply demarcated tender erythematous plaque in perianal region in children Scarlet Fever • Pyrogenic exotoxin (erythrogenic toxin) – mediated: types A, B, and C • Associated with streptococcal pharyngitis – positive throat culture (in early infection), ASO titer • Children 2–10 years of age • Enanthem: Exudative pharyngitis, strawberry tongue • Exanthem: Diffuse erythematous eruption with “sandpaper” texture, beginning on head and neck, and then generalizes, sparing palms/soles; circumoral pallor; Pastia’s lines (linear petechial patches in axillae and antecubital fossae • Desquamation upon resolution of exanthem, beginning on face/ears Purpura Fulminans • Group A streptococcal infection is the leading association • Hemorrhagic infarction of the skin caused by disseminated intravascular coagulation • Symmetric, large ecchymotic areas with irregular (“geographic”) borders on extremities, ears, and nose, most commonly Other Streptococcal Infections • Ecthyma • Impetigo (non-bullous) • Erysipelas • Cellulitis • Gangrenous cellulitis (infectious gangrene, necrotizing fasciitis) • Streptococcal toxic-shock–like syndrome • EndocarditisTrichomycosis Axillaris • Causative organism: Corynebacterium tenuis • Characteristic features: Yellowish brown concretions on axillary hair shafts • Treatment: Shaving; benzoyl peroxide gel; topical erythromycinTularemia • Causative organism: Francisella tularensis • Most commonly caused by contact with infected rabbits (e.g., hunters) • Ulceroglandular form is the most common – chancre like ulcer with raised borders and regional lymphadenopathy; typically on finger or hand • Other forms: Glandular, chancriform, oculoglandular, typhoidal, pulmonary, oropharyngeal, and meningeal • Treatment: Streptomycin Infectious Diseases of the Skin  293
  • 8. 8.2  VIRAL INFECTIONS Summary: DNA viruses mnemonic – H-H-A-P-P-P-y Table 8-4. DNA Viruses Virus Group Major Examples Herpesvirus Herpes simplex (HSV), varicella-zoster (VZV), cytomegalovirus (CMV), Epstein-Barr (EBV) Hepadnavirus Hepatitis B Adenovirus Numerous serotypes Papovavirus Human Papilloma Virus (HPV) Parvovirus* Erythema infectiosum Poxvirus Molluscum contagiosum, smallpox, orf, milker’s nodules *Single-stranded DNARNA Viruses Table 8-5. RNA Viruses Virus Group Major Examples Paramyxovirus Measles, mumps Togavirus Rubella Rhabdovirus Rabies Retrovirus HIV, HTLV Picornavirus Enterovirus: coxsackie virus (Hand-Foot-and-Mouth disease)Congenital Cytomegalovirus (CMV) • Infection during 1st and 2nd trimester - Highest risk for permanent abnormalities • Small for gestational age, microcephaly, retinitis, colobomas, intracranial calcifications •  #1 infectious cause of deafness and mental retardation in U.S. • Most common congenital viral infection • Part of TORCH syndrome (see below) – with “blueberry muffin baby” purpuraEpstein-Barr Virus Infects Blymphocytes Table 8-6. Epstein-Barr Virus Disease Important Features Infectious mononucleosis • Fever, pharyngitis, and lymphadenopathy • Malaise, headache, myalgias, hepatosplenomegaly • Commonly, morbilliform eruption after treatment with ampicillin • Affects teenagers and young adults Oral hairy leukoplakia • Slightly raised white plaque on lateral surface of tongue with a corrugated appearance • Seen in HIV and other immunocompromised states294    2011/2012 Dermatology In-Review l Committed to Your Future
  • 9. Exanthem Subitum (Roseola Infantum, Sixth Disease) • Caused by human herpesvirus 6, 7 (HHV-6, HHV-7) • High fever followed 4 days later by a sudden eruption of asymptomatic pink macules and papules with white halos as the fever subsides • Lesions appear first on trunk, then spread to extremities • Resolves within 1 to 2 days • Differential diagnosis: measles, rubella, scarlet fever, erythema infectiosum (see Parvovirus B19 infection)Hand-Foot-and-Mouth Disease • Coxsackievirus A16 or enterovirus 71 • Oral–oral and fecal–oral mode of transmission • Erythematous papules with grayish vesicle and surrounding red areola are characteristic cutaneous lesionsHerpangina • Group A coxsackievirus • Fever, headache, cervical lymphadenopathy • Gray-white papulovesicles in oral mucosa that ulcerate (commonly present on tonsillar fauces, palate)Herpes Simplex Virus (HSV-1, HSV-2) Clinical Presentations Primary Gingivostomatitis • Seen in children and young adults following primary HSV infection (usually HSV-1); occurs in only 1% of primary HSV infections of the lips or face • Presents with fever, sore throat, and painful vesicles/erosions on the tongue, palate, buccal and gingival mucosa • Erosions are covered with characteristic gray membrane Primary Genital Herpes • Most cases caused by primary infection with HSV-2 • Multiple painful erosions, often bilateral, on the ano-genital mucosa • Painful inguinal lymphadenopathy • Minority of cases may have concomitant aseptic meningitis with fever, nuchal rigidity, headache, photophobia • Dysuria and vaginal/urethral discharge may be present • Severity of symptoms peaks at days 8 to 10 Recurrent Genital Herpes • Tender, grouped erosions; non-indurated (unlike chancre of primary syphilis) • Much shorter duration of symptoms and more limited involvement of lesions compared to primary form • Greater recurrence rate with HSV-2 than with HSV-1 Recurrent Herpes Labialis • Typically affects skin-mucosa junction of mouth (more commonly than inside mouth) • Intra-oral lesions distinguished from aphthous ulcers by clustering of lesions in HSV vs. multiple discrete lesions in aphthous ulcers Infectious Diseases of the Skin  295
  • 10. Herpes Gladiatorum • Affects wrestlers and rugby players • Most common locations: face, lateral neck, medial arms Neonatal Herpes Simplex • Majority of cases acquired during delivery as neonate passes through infected vaginal canal • Clinical spectrum ranges from localized skin lesions to multi-systemic infection with encephalitis, hepatitis, pneumonia, and coagulopathy  • Use of scalp electrodes increase risk of neonatal transmission in HSV-infected mothers • In utero infections can rarely occur and are associated with fetal anomalies – microcephaly, encephalitis, intracranial calcifications Disseminated HSV u TIP • Occurs in young children (6 months aE zema Herpeticum (Kaposis Varicelliform Eruption) c to 3 years old), neonates, and W idespread HSV infection involving skin affected by: immunocompromised individuals • Atopic dermatitis • Dariers disease Herpes Simplex - Treatment • Hailey-Hailey, or severe seborrheic dermatitis Acyclovir • Guanosine analogue • Inhibits viral DNA polymerase after being phosphorylated by viral thymidine kinsase (TK), and 2 additional viral kinases Famciclovir • Prodrug of penciclovir; increased bioavailability and longer half-life • Also dependent on viral TK for activity Valcyclovir • L-valine ester of acyclovir with increased bioavailability • Viral TK-dependent; same mechanism of action as acyclovir • Thrombotic thrombocytopenic purpura reported using high doses in immunosup- pressed patients Acyclovir-resistant HSV* – Treatment • Foscarnet – directly inhibits viral DNA polymerase (without requiring phosphorylation by TK) • Cidofovir – inhibits viral DNA polymerase in a TK-independent fashion *Most commonly due to TK-deficient strains of HSVHerpes Zoster (Varicella-Zoster-Virus) Ramsay Hunt Syndrome • Caused by VZV infection of the geniculate ganglion • Zoster involves the external ear • Facial paralysis – ipsilateral • Tinnitus or other auditory symptomHuman Herpesviruses • HHV-6 – causes roseola infantum = exanthem subitum = Sixth disease • HHV-7 – also causes roseola • HHV-8 – Kaposi’s sarcoma, Castleman’s syndromeHuman Papillomavirus (HPV) • Genome encodes “E” (early) and “L” (late proteins) • E proteins (E1-8): participate in viral DNA replication • L proteins (L1-L2): structural proteins – form virion (the outer shell of the virus)296    2011/2012 Dermatology In-Review l Committed to Your Future
  • 11. Verrucous Carcinoma (HPV-associated) • Giant condyloma of Bushke-Lowenstein – on penis • Epithelioma cuniculatum – on sole of foot • Oral florid papillomatosis Table 8-7. HPV and Wart Type HPV Type Type of Wart 1 Palmo-plantar 2, 4 Common 3, 10 Flat 7 Butchers 13, 32 Oral focal epithelial hyperplasia 5, 8, 9, 12, 14, 15, 17, 19-26 Epidermodysplasia verruciformis 6, 11 Anogenital; Bushke-Lowenstein tumor 16, 18, 31, 33-35 High risk anogenital/cervical; Bowenoid papulosisMeasles • Caused by measles virus, a paramyxovirus • High fever • “3 C’s:” Cough, Coryza, Conjunctivitis • Koplik’s spots • Erythematous macules and papules after above 3-4 day prodrome – rash begins on face and then generalizes within 3 daysMilker’s Nodule • Caused by paravaccinia virus, a poxvirus of the genus Parapoxvirus • Transmitted to humans from infected cows • Typically presents as a single 1 cm erythematous nodule on the finger or forearm, but multiple lesions may develop in some cases • Self-limitedMolluscum Contagiosum • Caused by molluscum contagiosum virus (MCV), a poxvirus • Affects children, adultsOrf (Contagious Pustular Dermatitis, Contagious Ecthyma) • Caused by orf virus (OV), a poxvirus of the genus Parapoxvirus • Endemic in sheep, goats, and musk oxen, presenting as nodules on the nose and mouth • Transmitted to humans from infected animals • Most common in shepherds, farmers, and veterinarians • Typically presents as a papule/nodule on the dorsal index finger • 6 stages, each lasting 6 days: 1.) Papular – red papule 2.) Target – nodule with erythematous center, white middle ring, and erythematous halo 3.) Acute – red, weeping nodule 4.) Regenerative – crust with black dots on surface of nodule Infectious Diseases of the Skin  297
  • 12. 5.) Papillomatous – small papillomas 6.) Regressive – lesion crusts flattens, and ultimately resolvesParvovirus B19 Infection u TIP • Children: Erythema Infectiousum (Fifth disease) – aregnancy: Hydrops fetalis, spontaneous abor- P “slapped cheek” appearance is characteristic tion (highest risk in first half of pregnancy) • Adults: Acute arthropathy with fever and adenopathy; may develop a lacy, reticular macular eruption • Papular purpuric “gloves and socks” syndrome: erythema, petechiae, and edema on hands and feet along with fever and oral erosions • Aplastic crisis in patients with sickle-cell disease and other chronic anemias • Severe chronic anemia in immunocompromised patientsRubella • Erythematous macules and papules begins on face – then spreads to trunk in 24 hours (disappearing as it spreads) • Cervical, suboccipital, postauricular lymphadenopathy • Congenital infection: TORCH syndrome* with Blueberry Muffin Baby**; low birth weight, microcephaly, congenital heart disease; most severe when acquired in 1st trimester *TORCH Syndrome – Toxoplasmosis – hepatosplenomegaly – Other (syphilis, bacterial sepsis) – deafness – Rubella – microcephaly – CMV – chorioretinitis – HSV – thromboyctopenia **Blueberry Muffin Baby – Dermal extramedullary erythropoiesis – Generalized distribution of 1 to 7 mm purpuric papules, especially on head, neck, and trunk – Differential Diagnosis • TORCH • Parvovirus B19 • Hemolytic disease of the newborn • Hereditary spherocytosis • Twin transfusion syndrome • Neuroblastoma • Rhabdomyosarcoma • Langerhans’ cell histiocytosis • Congenital leukemiaSmallpox • Caused by variola, a poxvirus • Incubation period: lasts 12 days; viral replication occurs • Prodrome: 3 days of fever, malaise, severe headache, apprehension, back pain, and vomiting; few cases have a prodromal rash of macules, papules, or petechiae in a “swimming-trunk” distribution, which is pathognomonic •   eneralized centrifugal eruption: synchronously appearing papules, deep-seated vesicles, G pustules, central umbilication, and crusting over the course of two weeks; lesions are in the same stage of development and favor the head and extremities over the trunk298    2011/2012 Dermatology In-Review l Committed to Your Future
  • 13. • Diagnosis: Guarnieri’s bodies (cytoplasmic eosinophillic inclusions on light microscopy); identification of virus on electron microscopy of vesicular fluid or lesion scrapings; fluorescent antibody staining of lesional fluid or scrapings Complications of Smallpox Vaccination • Erythema multiforme-like eruptions • Bacterial superinfection – S. aureus, group A beta-hemolytic streptococci • Accidental inoculation – eczema vaccinatum may develop if inoculated onto dermatitic skin • Congenital vaccinia – following vaccination of a pregnant woman • Generalized vaccinia – children with isolated IgM deficiency are especially prone • Progressive vaccinia – secondary to an impaired immunological response to vaccinia; can occur either in normal or immunodeficient hosts • EncephalitisVaricella (Varicella-Zoster-Virus) Distinguishing Features (Compare to Smallpox) • Absent or mild prodrome • Lesions begin on face and spread to trunk • Centripetal distribution with fewest lesions on extremities • “Dew drops on a rose petal” – superficial vesicle with erythematous halo • Lesions in different stages of evolution • Rapid evolution (24h) of lesions from macule-papule-vesicle-crust Varicella in Pregnancy • First 20 weeks of gestation: Congenital Varicella syndrome - hypoplastic limbs, ocular and CNS abnormalities • 5 days before and 2 days after delivery: Neonatal Varicella - neonate develops varicella at 5 to 10 days of age because of inadequate transplacental delivery of maternal anti- varicella antibodies; treat with VZIG + IV-acyclovir8.3  MYCOBACTERIAL INFECTIONSLeprosy • Causative Organism: Mycobacterium leprae Characteristic Features u TIP • Transmitted from human to human most likely via a rmadillos may be a A respiratory secretions nonhuman source of infection • Spectrum of disease based on cell mediated immune a orderline forms are unstable; B response (see Table 8-8) “downgrading” (Type 1 reactions) • he polar forms of leprosy, TT and LL, do not evolve into T may occur any other form throughout the course of the disease • Indeterminate leprosy: Usually a solitary lesion; no sensory loss; can progress into lepromatous, tuberculoid, or borderline leprosy Treatment (WHO recommendations) Paucibacillary: D apsone 100 mg po qd for 6 months Rifampin 600 mg po q monthly for 6 months Multibacillary: Dapsone 100 mg po qd for 12 months Clofazimine 50 mg po qd for 12 months Rifampin 600 mg po q monthly for 12 months Clofazimine 300 mg po q monthly for 12 months (supervised) Infectious Diseases of the Skin  299
  • 14. Table 8-8. Leprosy TT BT BB BL LL TH1 cytokine profile: TH2 cytokine profile IFN-γ, IL-2, IL-12 IL-4, IL-10 Paucibacillary Multibacillary Lepromin test+ Lepromin test- ≤3 lesions 3–10 lesions Many lesions Lesions too Generalized that are smaller distributed numerous to and symmetrical than TT asymmetrically count; smaller distribution lesions predominate Anesthetic and Similar to TT Less anesthesia Minimal or no No loss of anhidrotic than TT sensory defects sensation or lesions sweating Type 2 Reaction: Erythema Nodosum Leprosum • Occurs most commonly in LL  • Bright pink, painful nodules arising in normal appearing skin  •  Multisystemic illness: fever, malaise, anorexia, arthralgias • Involves both upper and lower extremities, and not uncommonly, the face • Typically occurs after initiation of therapy • Treatment: ThalidomideTuberculosis Tuberculosis of the Skin (Summary) See Table 8-9 Miliary Tuberculosis of the Skin • Hematogenous spread of mycobacteria from fulminant tuberculosis of the lung or meninges • Immunosuppressed host – HIV, infants • Tuberculin test is negative (anergic) • Disseminated erythematous macules, papules, nodules, or purpuric lesionsAtypical Mycobacteria u TIP M. fortuitum, M. chelonei, M. abscessus a ost commonly cause post-injection M • “Rapid growers” abscesses; outbreaks following cosmetic • Found in soil, water, dust and animals surgery procedures have been reported • Infections occur after exposure to contaminated surgical instruments or following trauma • Typically presents with a single or multiple erythematous subcutaneous nodules on an extremity – sometimes in a sporotrichoid distribution • In addition to cutaneous infection, systemic involvement can also occur • Treatment: Surgical drainage/debridement followed by course of antimicrobial therapy (amikacin, clarithromycin, ciprofloxacin, imipenem and others) M. Marinum – Swimming Pool/Aquarium Granuloma u TIP • Begins as small papule at site of inoculation and a ssociated with skin injury followed by A evolves in to a nodule or granulomatous plaque, exposure to contaminated water – usually often with a verrucous surface from an aquarium, swimming pool, or lake • Sporotrichoid spread can occur • Treatment: Minocycline300    2011/2012 Dermatology In-Review l Committed to Your Future
  • 15. Table 8-9. Tuberculosis of the Skin (Summary) Tuberculosis Tuberculous Verrucosa Lupus Tuberculous Tuberculosis Chancre Cutis Vulgaris Scrofuloderma Gumma Cutis Orificialis Primary (exogenous) Exogenous Hematogenous, Contiguous spread Hematogenous Autoinoculation inoculation re-infection lymphatic, or contiguous onto skin from spread from underlying spread from distant site underlying advanced visceral of tuberculous infection tuberculous infection tuberculosis Non-sensitized host Sensitzed host Sensitized host with Sensitized host with Immunosuppressed Sensitized host with strong moderate to high low immunity host with diminishing immunity immunity immunity Pauci- or Multi- Paucibacillary Pauci-bacillary Multi- or pauci-bacillary Multi-bacillary Multi-bacillary bacillary, depending on stage of infection and strength of immune response · ainless red-brown P · lowly growing S B · rownish-red plaque · ubcutaneous nodules S · Subcutaneous · unched-out P papule that ulcerates verrucous · Apple-jelly” color on “ with purulent or abscesses ulcers with · uberculous primary T plaques with diascopy caseous drainage · ay form fistulas M undermined edges complex: regional irregular borders · ead/neck involvement H · ay develop sinuses M and ulcers · On lymphadenopathy, · ypically on hand T in 90% of cases and ulcers with · ypically on trunk, T mucocutaneous 3-8 weeks post granulating bases head, or extremities junctions of infection · ccurs most commonly O mouth, genitalia over cervical lymph nodesInfectious Diseases of the Skin  301
  • 16. 8.4  SEXUALLY TRANSMITTED DISEASESGenital Ulcer Disease • See Table 8-10Gonococcemia Causative Organism: Neisseria gonorrhoeae Clinical Features • Sparsely distributed hemorrhagic vesiculopustules with erythematous bases on palms, soles and over joints • Fever, chills, arthralgias, malaise • Recurrent cases may be associated with complement deficiencies (especially C5-C8) • Treatment: Ceftriaxone IVSyphilis Causative Organism: Treponema pallidum (a spirochete) Clinical Features Primary: chancre – ulcer with raised, indurated borders • Occurs 10 days to 3 months after exposure • Lasts 3 to 12 weeks Secondary: variable involvement of skin and mucous membranes  •  idespread cutaneous eruptions, ham-colored macules on the palms and soles, mucous W patches, condyloma lata, split papules, “moth-eaten” alopecia • Lasts 4 to 12 weeks Latent • Early ( 1 year) • Late (1 year) Tertiary • Late benign – no cardiovascular or CNS involvement; gummas • Cardiovascular Syphilis • Neurosyphilis Congenital Early ( 2 years of age) • Low birth weight • Bone disease (“saw-tooth” appearance of metaphysis) • Rhinitis (“snuffles”) • Rhagades (Parrot’s lines) • Pseudoparalysis of Parrot • “Syphilitic pemphigus” • Lymphadenopathy (epitrochlear) • Neurosyphilis302    2011/2012 Dermatology In-Review l Committed to Your Future
  • 17. Table 8-10. Genital Ulcer Diseases (overview)* Primary Syphilis Chancroid Granuloma Lymphogranuloma Inguinale Venereum Causative T. pallidum H. ducreyi Calymmatobacterium Chlamydia trachomatis Organism granulomatis L1, L2, L3 Characteristic P • ainless chancre with • Soft, painful/tender • rimary lesion: papule, P • ainless, soft erosion that P Clinical “ham-colored” base and chancre with ragged subcutaneous nodule heals spontaneously Features sharply defined, indurated edges (pseudobubo), or ulcer • econdary inguinal ade- S border • School of fish” on Gram “ • our clinical forms: F nopathy with fluctuant, • hancre has cartilage-like C or Giemsa stain Ulcerovegetative (most tender nodes above and consistency and exudes common), Nodular, below Poupart’s ligament— clear fluid Hypertrophic, and Cicatricial “groove sign” (can be • Bilateral • onnovan bodies D bilateral) (“safety-pin” shaped • erologic diagnosis by S intracytoplasmic inclusions complement fixation test in macrophages) seen on microscopy Treatment Penicillin Azithromycin TMP-SMX Doxycycline Ceftriaxone Doxycycline Ciprofloxacin Erythromycin Erythromycin Ciprofloxacin *Genital Herpes discussed under “Herpes Simplex Virus”Infectious Diseases of the Skin  303
  • 18. Late ( 2 years of age) • Mulberry molars • High-arched palate • Hutchinson’s teeth (widely-spaced, peg-shaped upper incisors)* • Saddle nose • Saber shins • Clutton’s joints (non-tender, bilateral swelling of knees) • Higoumenakis sign (unilateral enlargement of medial clavicle) • Eighth nerve deafness* • Intersitial keratitis* • Retinitis • Gummas – nose and palate • Dactylitis *Hutchinson’s triad Serology Nontreponemal* • VDRL  – Reactive 4 to 5 weeks after infection; often reverts to nonreactive during late latent stage   – Becomes nonreactive after treatment • RPR – Similar features as VDRL *Biologic False Positive Nontreponemal Tests • Pregnancy • Other spirochete infection (Leptospirosis, Lyme disease, Relapsing fever, Rat-bite fever, Yaws/Pinta) • Viral infections (CMV, HIV, infectious mononucleosis) • Autoimmune diseases (anitphospholipid syndrome, SLE) • Malaria • Lepromatous leprosy • Drug abuse Treponemal • Fluorescent Treponemal Antibody Absorption (FTA-ABS) test – Positive by 3rd week of infection  – Remains positive after treatment – The most sensitive serologic test in primary syphilis • MHA-TP – Similar serologic features as FTA-ABS, except less sensitive during primary syphilis • Enzyme-linked immunosorbent assay (ELISA)- captia (IgM) EIA – Serologic test of choice in early primary and congenital syphilis because it is the first to become reactive  – Useful during early infection, but less sensitive in late disease because of reduction in IgM production – 100% specificity304    2011/2012 Dermatology In-Review l Committed to Your Future
  • 19.  Treatment Primary and Secondary (without end-organ involvement) Early Latent • Benzathine s G, 2.4 million units IM x 1 dose – In cases of penicillin allergy, doxycycline 100 mg po BID for 2 weeks is the treatment of choice Indeterminate or Late Latent Tertiary (without neurosyphilis) • Benzathine penicillin G, 2.4 million units x 3 doses, 1 week apart Complications of Treatment: Jarisch-Herxheimer Reaction • Fever • Headache • Lymphadenopathy • Flare of skin lesions • Myalgias • Elevated white count • Caused by the release of inflammatory cytokines, particularly, TNF-α, due to phagocytosis of spirochetes following antibiotic administration8.5  NONVENEREAL TREPANOMATOSES Table 8-11. Pinta Yaws Endemic SyphilisCausative Organism T. carateum T. pertenue T. pallidumTreatment Penicillin Penicillin Penicillin8.6  PARASITIC INFECTIONSLeishmaniasis Table 8-12. Old World - Africa, Middle East, New World - South and Central America** Southern Europe, AsiaSpecies L. major L. mexicana complex L. tropica L. braziliensis complex L. aethiopica L. amazonensis L. infantum L. donovani* *Visceral leishmaniasis (kala-azar) – India, Kenya **New World leishmaniasis also reported in Southern U.S. (Texas) Infectious Diseases of the Skin  305
  • 20. Cutaneous Leishmaniasis (CL) Table 8-13. Cutaneous Leishmaniasis Old World New WorldSpecies L. major L. mexicana complex L. tropica L. braziliensis complex L. aethiopica L. amazonensis L. infantum Mucocutaneous Leishmaniasis (MCL) • L. aethiopica (Old World) • L. braziliensis complex (New World) Visceral Leishmaniasis (VL; kala-azar) • L. donovani • L. infantum Vectors: Sandflies belonging to two different geni, depending on geographic region • Phlebotomus (Old World) • Lutzomyia (New World) Diagnosis • Culture in Novy-MacNeal-Nicolle (NNN) medium • Histopathology: amastigotes identified in histiocyte cytoplasm as oval bodies with nucleus and kinetoplast (after staining with Giemsa) • PCR for species identification Treatment • Pentavalent antimony (sodium stibogluconate)Trypanosomiasis (Sleeping Sickness) Table 8-14. TryanosomiasisClinical Form Feature Causative Organism Vector Characteristic ClinicalAfrican Trypanosomiasis T. brucei gambiense Tsetse fly Winterbottoms sign (West Africa) (Glossina spp.) (posterior cervical lymphadenopathy) T. brucei rhodesiense (East Africa)American T. cruzi (Central and Reduviid bug Romañas sign (eyelidTrypanosomiasis South America) (Reduviidae spp.) edema and conjuctivitis(Chagas disease) at site of inoculation)Filariasis Lymphatic Filariasis Clinical Features • Lymphedema • Elephantiasis Causative Organisms • Brugia malayi • Brugia timori • Wuchereria bancrofti Vectors: Infection spread by mosquitoes belonging to genera Aedes, Anopheles, Culex, orMansonia306    2011/2012 Dermatology In-Review l Committed to Your Future
  • 21. Dracunculiasis • Causative organism: Dracunculus medinensis • Vector/mode of infection: Cyclops copepods (aquatic arthropods), which are ingested by humans after drinking copepod-infested water • Characteristic feature: The worm can be found emerging from the skin, most often on the lower extremity • Prevent by filtering water Table 8-15. Dracunculiasis Loiasis OnchocerciasisCausative Organism Loa Loa Onchocerca volvulusVector Mango flies or Deerflies of genus Blackflies of genus Simulium ChrysopsCharacteristic Clinical Features • Calabar swellings • Pruritic papules • Adult worm migrating across • Depigmented macules/patches conjunctivae (eye worm) (Leopard skin) • Onchocercal nodules (over bony prominences) • Ocular involvement may lead to blindnessTreatment Diethylcarbamazine (DEC) IvermectinStrongyloidiasis • Causative organism: Strongyloides stercoralis • Mode of infection: Penetration of larvae through skin or mucous membranes, usually from contact with contaminated soil. Transmission through oral-anal intercourse also occurs • Characteristic features: – Cutaneous strongyloidiasis (Larva Currens, Ground Itch): Serpiginous urticarial plaques on buttocks, groin, or trunk that migrate up to 5–10 cm per hour – Disseminated strongyloidiasis: “Thumbprint” purpura on periumbilical skin and widespread petechiae on trunk/proximal extremitiesCercarial Dermatitis (Clam Digger’s Itch, Swimmer’s Itch) u TIP a haracteristic Features: C • Causative organism: Cercarial forms of flatworms of the family pruritic papules and papulo- Schistosomatidae vesicles on uncovered skin • Mode of infection: Penetration of skin while bathing in infested fresh or salt water in Northern United States and Canada u TIPSeabather’s Eruption a haracteristic Features: C • Causative organisms: Larval forms of Edwardsiella lineata (sea pruritic erythematous papules anemone) and Linuche unguiculata (thimble jellyfish) or wheals in areas covered by • Mode of infection: Contact with larvae while swimming in salt swim wear water in Southern U.S. and Caribbean, as well as off coast of Long Island, NY; larvae become trapped beneath swim wear Infectious Diseases of the Skin  307
  • 22. 8.7  RICKETTSIAL DISEASES (see Table 8-16) • Caused by obligate intracellular coccobacilli • Transmitted by arthropod vectors • Treatment: Tetracyclines (doxycycline preferred) Table 8-16. Rickettsial Diseases Causative Organism Vector Rocky Mountain R. rickettsii 1.) Western U.S. - Dermacentor andersoni Spotted Fever 2.) Eastern U.S. - Dermacentor variabilis Rickettsialpox R. akari Liponyssoides sanguineus - Mite of the house mouse Epidemic Typhus R. prowazekii Pediculus humanus corporis - human body louse Endemic Typhus R. typhi Xenopsylla cheopis - rat flea Scrub Typhus Orientia tsutsugamushi Chiggers - trombiculid mite larvae Q Fever Coxiella burnetii Dried tick feces which are inhaled Ehrlichiosis 1.) E. chaffeensis 1.) Amblyomma anericanum 1.) Human Monocytic Ehrlichiosis 2.) Human Granylocytic 2.) Ixodes sapularis, Ixodes pacificus 2.) Human Granulocytic Ehrlichiosis (HGE) agent Ehrlichiosis RE F E RE N C E S1. Swartz M.N., Weinberg A.N., Lee P.K., Zipoli M.T., Johnson R.A., Resnick S.D., Elias P., Tsao H., Berger T.G., Bravo F., Tappeiner G., Wolff K., Goihman-Yahr M., McNeil M.M., Brown J.M., Rea T.H. Modlin R.L., Asbrink E., Hovmark A. Bacterial Diseases with Cutaneous Involvement. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in general medicine. 5th ed. New York: McGraw-Hill, Health Professions Division, 2003: 1843-1980.2. Lowy D.R., Gellis, S.E., Cooper L.Z., Dolin R., et al. Viral and Rickettsial Diseases. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in general medicine. 5th ed. New York: McGraw-Hill, Health Professions Division, 2003: 2035-2051; 2054-2118; 2152-2163.3. Sanchez M.R., Lautenschlager S., Eichmann A.R., Rothenberg R., Feingold D.S., Mansur C.P. Sexually Transmitted Diseases. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in general medicine. 5th ed. New York: McGraw-Hill, Health Professions Division, 2003: 2163-2214.4. Klaus S.N., Frankenburg S., Dhar A.D., Lucchina L.C., Wilson M.E. Infestations. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in general medicine. 5th ed. New York: McGraw-Hill, Health Professions Division, 2003: 2215-2260.5. Stone S.P. Scabies and Pediculosis. In: Freedberg IM, Eisen AZ, Wolff K, et al., eds. Fitzpatrick’s Dermatology in general medicine. 5th ed. New York: McGraw-Hill, Health Professions Division, 2003: 2283-2288.6. Despommier D.D., Gwadz R.W., Hotez P.J. Parasitic Diseases. 3rd ed. New York: Springer-Verlag, 1994: 40-61; 190-218.7. Odom R.B. James W.D. Berger T.G. Andrew’s Diseases of the Skin: Clinical Dermatology. 9th ed. Philadelphia: W.B. Saunders Company, 2000: 307-357; 417-573.8. Center for Disease Control, National Center for Infectious Diseases, Division of Viral and Rickettsial Diseases, Dorsainvil, P.A., Cunha B.A., Relapsing Fever. Dixon T. C., Meselson M., Guillemin J., Hanna P. C. Anthrax. N Engl J Med 1999; 341: 815-826.11. Leonard A.L., Brown, L.H. Atypical Mycobacterial Outbreaks Associated with Cosmetic Surgery and Aesthetic Procedures, Cosmetic Dermatology, October 2004: 17(10): 636-640.308    2011/2012 Dermatology In-Review l Committed to Your Future
  • 23. NOTES Infectious Diseases of the Skin  309
  • 24. NOTES310    2011/2012 Dermatology In-Review l Committed to Your Future