This chapter discusses several dermatological emergencies including: 1) Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) which are characterized by severe blistering of the skin and mucous membranes that can lead to life-threatening complications. Early referral to a specialist center or burns unit is important. 2) Erythroderma which refers to inflammation of all the skin and can cause hypothermia, cardiac failure, fluid loss and other metabolic problems due to the skin being the largest organ. 3) Angioedema which involves swelling beneath the skin and can compromise breathing if the lips, tongue or throat swell. Adrenaline and steroids

1. Dermatology Lecture Notes, Eleventh Edition. Robin Graham-Brown, Karen Harman and Graham Johnston.
© 2017 John Wiley & Sons, Ltd. Published 2017 by John Wiley & Sons, Ltd.
Miscellaneous: of mixed composition or character; of
various kinds; many‐sided.
Concise Oxford English Dictionary
This chapter is a mixed bag: it covers a number of
common and/or important skin disorders that have
not found a place elsewhere.
Urticaria and
angioedema
‘Urticaria’ is the clinical term for a group of disorders
characterized by the formation of weals: swellings of
the skin that disappear, leaving no visible sign. Most
of us have experienced one common form – after
falling (or being pushed) into nettles (the term ‘­nettle
rash’ is used commonly for urticaria). The main
pathological change is ­dermal oedema due to vascu-
lar dilatation, often in response to histamine (and
probably other mediators) released from mast cells.
In some patients, there are also small numbers of
lymphocytes, indicating an autoimmune aetiology.
Clinical features
The skin itches or stings. Weals develop, white at
first, then pink with a white rim. Lesions can
become very extensive and appear in many sites at
once, but always clear spontaneously within a few
hours, even though new lesions may continue to
develop.
Typical lesions of urticaria are shown in Figure 16.1.
A frequent accompanying feature is angioedema,
in which oedema extends into subcutaneous
­tissues, especially around the eyes and lips and
in the mouth and pharynx. The swelling may be
Miscellaneous
erythematous and
papulosquamous
disorders, and light‐
induced skin diseases
16

2. 138 Chapter 16: Miscellaneous erythematous and papulosquamous disorders
alarming, occasionally resulting in complete clo-
sure of the eyes, swelling of the lips and tongue and
compromise of the airway.
Urticaria and angioedema may form part of a sys-
temic anaphylactic reaction.
Clinical forms of urticaria and
angioedema
Acute urticaria
Attacks last only a few hours or days. Common causes
include the following:
1 Contact with plants (e.g. nettles), animal fur (e.g.
dogs, cats, horses) or foods (e.g. milk, egg white).
2 Ingestion of foods, especially milk, eggs, nuts,
shellfish and strawberries.
3 Ingestion of drugs, e.g. aspirin and penicillin.
4 Infections, e.g. helicobacter, viral hepatitis,
mycoplasma.
People who have atopy (with asthma, eczema or hay
fever) are more susceptible. The reaction is gener-
ally triggered by antigen/immunoglobulin E (IgE)
complexes, which attach to and degranulate mast
cells, releasing histamine and other vasoactive com-
pounds; some reactions (e.g. to aspirin) are due to
direct mast cell degranulation.
Chronic urticaria
If the problem extends beyond 6 weeks, it is classified
as chronic. It can last for many weeks, months or
years. Contrary to the deeply held convictions and
expectations of most patients, a single causative fac-
tor is rarely found. Current evidence indicates that in
almost all patients, urticaria that pursues a protracted
course is caused by an autoimmune process or one of
the physical stimuli discussed in the next subsection.
The physical urticarias
Severalphysicalinsultsmaytriggerurticarialresponses:
1 Dermographism: weals appear after scratch‐marks
(Figure 16.2); this may occur alone or with other
forms of urticaria.
2 Pressure (delayed): weals develop up to 24 hours
after pressure is applied (e.g. by a bag hanging over
the shoulder).
3 Cholinergic urticaria: mostly affects young men;
sweating (e.g. following exercise or emotional
upset) is accompanied by small white weals with a
red halo on the upper trunk.
4 Cold: contact with cold objects or blasts of cold air
induce the formation of weals.
5 Water.
6 Sunlight.
7 Heat.
Chronic spontaneous/idiopathic
urticaria
Chronic spontaneous/idiopathic urticaria is diag-
nosed when no other trigger can be identified.
Patients require careful assessment and a clear expla-
nation of what they can realistically expect.
Hereditary angioedema
In this very rare autosomal dominant condition:
1 C1 esterase inhibitor is lacking or defective.
2 There are sudden attacks of angioedema, which
can be life‐threatening.
3 The gut may be affected, giving rise to spasms of
abdominal pain.
Figure 16.1 Urticaria: multiple irregular pink weals
with a white border. Each individual lesion comes
and goes within 24 hours. Note the complete
absence of scaling.

3. Chapter 16: Miscellaneous erythematous and papulosquamous disorders 139
Treatment of urticaria
If a possible trigger can be elicited from the his-
tory, it should be avoided. Aspirin and aspirin‐like
substances should be avoided by anyone prone
to urticaria, because of their effect on mast cell
mambranes.
Most types of urticaria respond to H1
‐receptor anti-
histamines, although some of the rarer physical forms
do not. A large range of agents is available, many of
which cause central nervous system (CNS) depres-
sion, but several newer antihistamines have little or
no sedative effect (e.g. desloratadine, ­levocetirizine,
fexofenadine). These are now drugs of first choice. It
may help to add an H2
‐receptor antagonist (cimeti-
dine, ranitidine), but this is controversial. Experts
­recommend escalating the dose gradually to levels
well beyond those recommended in the British
National Formulary (BNF), if necessary.
It is sometimes necessary to use other agents,
such as montelukast, systemic steroids, ciclosporin
and adrenaline. The biologic agent omalizumab
(anti-IgE) is now licenced for treatment resistant
cases.
Urticaria pigmentosa
Abnormal accumulations of mast cells result in
multiple pigmented macules, which cause urticaria
on being rubbed or warmed (see also Chapter 13).
Urticaria in systemic disease
An urticarial eruption may be part of some systemic
disorders, including systemic lupus erythematosus
(SLE) and hepatitis B.
Erythema multiforme
The classic lesion of erythema multiforme is the
‘iris’ or ‘target’ lesion (Figure 16.3): a round or oval
area of erythema, with a dusky, purplish centre.
Sometimes the centre becomes paler and a blister
forms.
History
Lesions appear suddenly, enlarge over the course of a
few days and fade (often leaving pigmentary distur-
bances). The whole process settles in about 3 weeks.
Repeated episodes are rare, but can be triggered by
herpes simplex virus (see later).
Figure 16.2 Dermographism spelling out the name of
one of Leicester’s main hospitals.
Management of urticaria
• Acute attacks: a few days’ treatment is usually
sufficient.
• Chronic urticaria: give a dose of antihistamine,
which suppresses the eruption completely;
if successful, maintain this dose for several
months and gradually withdraw treatment.
Resistant disease may require the addition of
montelukast, ciclosporin, systemic steroids or
the biologic agent, omalizumab.
• Angioedema: may require parenteral therapy
with adrenaline, antihistamines and steroids.
• Anaphylaxis: adrenaline is required.
• Hereditary angioedema: does not respond to
antihistamines or steroids. Danazol works by
increasing levels of the missing enzyme. Purified
enzyme preparations are available for acute
attacks.

4. 140 Chapter 16: Miscellaneous erythematous and papulosquamous disorders
Aetiology
Erythema multiforme may occur out of the blue, but
there are several recognized triggers, of which infec-
tion is by far the most common (see box).
Examination
The distribution characteristically includes extensor
surfaces of the arms and legs. Mucous membranes
may be affected (Figure 16.4). An important diagnos-
tic pointer is involvement of the palms and soles. Skin
lesions may blister (bullous erythema multiforme).
Treatment
Erythema multiforme is self‐limiting, and treatment
is not usually required.
Stevens–Johnson syndrome
Patients with Stevens–Johnson syndrome (SJS)
experience a major systemic disturbance. There
is an acute onset, with severe inflammation of
Figure 16.3 Target lesions of
erythema multiforme.
Triggers for erythema multiforme
• Herpes simplex virus: the most common trigger;
as herpes may be recurrent, so may herpes‐
related erythema multiforme.
• Other viruses: orf, hepatitis, mumps.
• Mycoplasma.
• Cancers and, possibly, radiotherapy.
• Connective tissue diseases.
• A wide variety of drugs.
Figure 16.4 Erosions on the lips in
erythema multiforme.

5. Chapter 16: Miscellaneous erythematous and papulosquamous disorders 141
conjunctivae, mouth and genitalia, which may
prevent normal eating, affect micturition and
cause ocular scarring. Patients occasionally die of
severe ­bronchopulmonary involvement or renal
failure.
Treatment
Close attention must be given to fluid balance and
nutrition. The role of systemic steroids is controver-
sial, because the morbidity from steroids probably
outweighs that from the disease.
Erythroderma (exfoliative
dermatitis)
In exfoliative dermatitis, most of the skin becomes
red, inflamed and oedematous. There may be some
scaling. The following are the four most important
causes:
1 Psoriasis.
2 Eczema/dermatitis.
3 Drug reactions.
4 Lymphomas (especially cutaneous T‐cell
lymphoma).
The correct management depends on the underlying
disease process, as this affects the optimum treat-
ment (see Chapter 3).
Erythema nodosum
This condition usually affects children and young
adults, and is characterized by the development
of multiple, tender, erythematous nodules, usu-
ally on the shins (Figure 16.5), but occasionally
also on the forearms. As each nodule regresses,
it changes colour from red to purple to yellow–
green – like a fading bruise. Pathologically, erythema
nodosum is an inflammatory process of fat
(panniculitis).
It is thought to be a hypersensitivity reaction trig-
gered by the following causes:
• Streptococcal infection.
• Drugs.
• Sarcoidosis.
• Primary tuberculosis (TB).
• Inflammatory bowel disease.
• Lymphoma.
In some cases, no precipitating factor is discovered.
Investigation of a patient with erythema nodo-
sum should include culture of a throat swab,
antistreptolysin titre, chest radiograph and a
search for sarcoid, a lymphoma or underlying
tuberculosis (TB).
Treatment
In most cases, bed rest and simple analgesia are all that
is required. The lesions will gradually resolve over a
period of a few days. Occasionally, a course of oral ster-
oids is indicated.
Figure 16.5 Lesions of erythema nodosum on the
shins.

6. Dermatology Lecture Notes, Eleventh Edition. Robin Graham-Brown, Karen Harman and Graham Johnston.
© 2017 John Wiley & Sons, Ltd. Published 2017 by John Wiley & Sons, Ltd.
Introduction
Dermatological emergencies are rare, but early recog-
nition and referral are just as important in dermatol-
ogy as in any other branch of medicine. You are most
likely to pick up the specifics of management if you
encounter one of these situations while in your first
years in medicine.
Toxic epidermal
necrolysis and Stevens–
Johnson syndrome
Although technically toxic epidermal necrolysis
(TEN) and Stevens–Johnson syndrome (SJS) are
separate conditions, most authorities consider
them together for the purpose of diagnosis and
management (see Chapters 15 and 16). TEN and SJS
are terms used for blistering damage that occurs
secondary to inflammation of the epidermis which
results in very serious damage. The changes may
be so severe that the epidermal layer dies and is
shed, leaving an exposed, oozing dermis (see
Figure 15.12). The distinction between the two is
based on the area of epidermal loss. In TEN, it’s
>30%; in SJS, it’s <10%; 10–30% involvement is
­classified as ‘SJS/TEN overlap’. The skin can initially
become itchy, or patients may complain of a burn-
ing sensation and a fever. Mucosal involvement is
common and internal epithelial surfaces (gastrointes-
tinal tract, lung, etc.) may also be involved. Early refer-
ral either to specialist centres with highly experienced
dermatology nursing care and a general intensive care
unit (ICU) or to a burns unit gives patients the best
chance of survival. Beyond general, supportive meas-
ures, there is some debate as to best treatment, but
intravenous immunoglobulin and ciclosporin may
have a role.
Erythroderma
The term ‘erythroderma’ refers to the clinical state of
inflammation of all the skin (see Chapter 16).
Erythroderma is not a pathological diagnosis.
Clinical features
These are generally the same, regardless of the under-
lying cause: the skin is red, hot (Figure 3.1) and scaly;
there may be generalized lymphadenopathy; there is
a loss of control of temperature regulation; and there
are bouts of shivering as the body attempts to com-
pensate for heat loss by generating metabolic heat.
Given that the skin is the largest organ of the body,
it is not surprising that this can result in haemody-
namic and metabolic problems:
• Hypothermia from heat loss.
• High‐output cardiac failure.
• Hypoalbuminaemia.
• Fluid loss.
Emergency dermatology
3