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394 Chapter 9: Dermatology and soft tissues

Prognosis Investigations
Withouttreatmentpemphiguscarriesahighriskofmor- Biopsy of an intact blister for light microscopy and direct
tality. With combination therapy the mortality rate is immunofluorescence for IgG and complement seen in
around 5%, mainly due to sepsis and other drug compli- a linear pattern along the basement membrane of the
cations. Most patients require long-term immunosup- blister.
pressive treatment with maintenance therapy to remain
in remission. Management
Patients have traditionally been treated with systemic
corticosteroids, with azathioprine, cyclophosphamide
Pemphigoid
and methotrexate used as steroid-sparing agents. Recent
Definition data however suggests that topical corticosteroid therapy
Pemphigoid is a chronic, blistering autoimmune disease is effective in both moderate and severe pemphigoid.
of the skin.
Prognosis
Often self-limiting with remission allowing cessation of
Incidence
treatment after 1–2 years.
Twice as common as pemphigus.
Age Dermatitis herpetiformis
Mainly affects patients over 60 years.
Definition
Dermatitis herpetiformis is a primary blistering disorder
Sex associated with coeliac disease and other autoimmune
M = F disorders.

Aetiology/pathophysiology Prevalence
Linear polyclonal IgG autoantibodies and complement 1in 350–400 patients with coeliac disease.
are found at the junction of the dermis and epidermis
causing the release of proteolytic enzymes, which dam- Age
age the basement membrane. Circulatory autoantibod- Teenagers and young adults.
ies against basement membrane glycoproteins BP230
and BP180 can be demonstrated in the serum of most Sex
patients. These may however result from keratinocyte M > F
damage rather than be the cause. Individual’s HLA
haloptype may make them susceptible to production of Aetiology
theseautoantibodies.Drugsincludingpenicillamineand Eighty-five per cent of individuals with dermatitis her-
furosemide may cause an acute pemphigoid, which re- petiformis have small bowel mucosal changes with vari-
solves on stopping the medication or they may unmask ablevillousatrophyonsmallbowelbiopsyeveniftheydo
latent pemphigoid that persists and behaves like non- not have the clinical features of coeliac disease. Both dis-
drug-induced illness. orders have similar HLA haplotypes and autoantibodies
to endomysial, gliadin and reticulin antigens. Dermatitis
Clinical features herpetiformis is also associated with other organ specific
Patients present with widespread blisters and erosions autoimmune conditions.
typically in the flexures, groin and axillae, which are of-
tenitchy.Cicatricialpemphigoidpredominantlyinvolves Clinical features
the mucous membranes, especially the oropharynx and Erythematous itchy papules and vesicles over the exten-
genital region with scarring. sor surface of the extremities and on the trunk.