A 34-year-old man presents with a three week history of an intensely itchy rash on the back of his elbows. On examination he has a symmetrical vesicular rash on the extensor aspects of his arms.
Which one of the following antibodies is most likely to be positive?
Correct Answer B: Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
Dermatitis herpetiformis Features:
Diagnosis:
Management:
clustered lesions on the elbows in dermatitis herpetiformis.
Direct immunofluorescence of dermatitis herpetiformis showing granular deposition of IgA in dermal papillae.
A 65-year-old woman presents with bullae on her forearms following a recent holiday in Spain. She also notes that the skin on her hands is extremely fragile and tears easily. In the past the patient has been referred to dermatology due to troublesome hypertrichosis.
What is the most likely diagnosis?
Correct Answer E: Porphyria cutanea tarda is the most common hepatic porphyria. It is due to an inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, oestrogens.
Porphyria cutanea tarda:
Porphyria cutanea tarda Features:
Investigations:
Porphyria cutanea tarda: erosions, blisters, pigmentary changes and scarring.
Facial hypertrichosis in porphyria cutanea tarda.
A 34-year-old man comes for review. Over the past two weeks he has developed a number of painful, erythematous lesions on his shins. He has no dermatological history of note and is usually fit and well. On examination the lesions are consistent with erythema nodosum. You arrange some baseline investigations. He asks what is likely to happen.
What is the most appropriate response?
Correct Answer C:
Erythema nodosum:
Overview:
Causes:
A 64-year-old woman presents with severe mucosal ulceration associated with the development of blistering lesions over her torso and arms. On examination the blisters are flaccid and easily ruptured when touched.
Correct Answer A: Pemphigus vulgaris is an autoimmune disease caused by antibodies directed against desmoglein, a cadherin type epithelial cell adhesion molecule. It is more common in the Ashkenazi Jewish population.
Blisters/bullae:
Pemphigus vulgaris Features:
Pemphigus vulgaris: irregular persistent oral erosions.
Pemphigus vulgaris-New disease onset in the second trimester showing pink scaly plaques and erosions on the back.
Indirect immunofluorescence using the patient’s serum and showing intercellular immunoglobulin G with intraepidermal split.
A 17-year-old man presents with a 2 week history of abdominal pain, diarrhoea and repeated episodes of flushing. Examination reveals urticarial skin lesions on the trunk.
What test is most likely to reveal the diagnosis?
Correct Answer E: Urinary histamine is used to diagnose systemic mastocytosis.
Given the history of diarrhoea and flushing a diagnosis of carcinoid syndrome should be considered, which would be investigated with urinary 5-HIAA levels. This would not however explain the urticarial skin lesions. In a young person a diagnosis of systemic mastocytosis should be considered. Another factor against carcinoid syndrome is the age of the patient - the average age of a patient with a carcinoid tumour is 61 years.
Systemic mastocytosis: Systemic mastocytosis results from a neoplastic proliferation of mast cells.
Features:
Urticaria pigmentosa lesions on the trunk of a child.
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