Dermatitis Herpetiformis

Question 1

What is Dermatitis Herpetiformis?

Answer 1

Dermatitis Herpetiformis is a rare skin disorder associated with coeliac disease. Herpetiformis refer to the fact the rash often resembles herpes zoster (shingles or chickenpox).
Pretty rare.

Question 2

Pathophysiology of Dermatitis Herpetiformis?

Answer 2

• Deposition of IgA in papillary dermis causing an immunological cascade
• Immunologic response to chronic stimulation of the gut mucosa. IgA react to GLUTEN TISSUE TRANSGLUTAMINASE (t-TG) in the gut, and EPIDERMAL TRANSGLUTAMINASE (e-TG)
• genetic predisposition with HLA expression (10% have affected relative)
• adulthood 20-40yrs
• Coeliacs disease
• M:F 2:1

Question 3

Signs and symptoms of Dermatitis Herpetiformis?

Answer 3

• “suicidally itchy” blisters and papule. Intensely pruritic
• scratched blisters appear as papules
• intermittent cutaneous lesions mainly affecting BUTTOCKS, KNEES and ELBOWS
• rarely any bowel symptoms of coeliacs disease

Question 4

Management of Dermatitis Herpetiformis?

Answer 4

Gluten free for life to:

1. control symptoms
2. reduce risk of small bowel lymphoma

To help get things under control:

• DAPSONE (Abx) 50mg OD
• SULPHAPYRIDINE (sulphonamide abx)
• BETAMETHASONE 0.05% potent topical steroid

Question 5

What are the side effects of dapsone in dermatitis herpetiformis?

Answer 5

Effect mangement but needs monitoring

SE:
widespread rash
haemolytic anaemia
agranulocytosis