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Mixed diagnoses – 10 cases (8 of 11)

For each of the ten cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.

Each case should take approximately five minutes to complete. There is a list of suggested further reading material at the end of the quiz.

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Case 2

A 34-year-old man presents with an itchy rash that has failed to respond to potent topical steroids used over the last year. Examination reveals excoriated papules and a small number of vesicles on knees, buttocks, forearms and scalp.

The patient has dermatitis herpetiformis, characterised by groups of vesicles on the extensor aspects of the skin and marked pruritus.

Dermatitis herpetiformis is an autoimmune skin disease associated with gluten-sensitive enteropathy. Gliadin in wheat appears to be responsible.

Biopsy of a new vesicle for histology and direct immunofluorescence. The characteristic histologic features are granular IgA deposits in the papillary dermis and neutrophils in the same region.

Serum for autoantibodies to gliadin and endomysium

Blood count, iron and folate studies to assess intestinal malabsorption

Small bowel biopsies Nearly all patients with dermatitis herpetiformis have villous atrophy due to gluten enteropathy (coeliac sprue). Some are symptomatic with diarrhoea, bloating and/or tiredness.

Most patients obtain excellent control with the following:

Dapsone; initial dose 50mg building up to 300mg daily if necessary, providing haemoglobin level is adequate.

If dapsone results in unacceptable side effects, sulphapyridine 1-2 g/day can be used.

Life long gluten-free diet. Many patients can significantly reduce the requirement for dapsone and are thought to minimise their risk of small bowel lymphoma.

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