
Introduction
Dermatitis herpetiformis is a rare skin disorder associated with coeliac disease. The name herpetiformis refers to the fact that the rash often resembles the rash caused by herpes zoster (shingles and chickenpox).
Aetiology
- Adulthood (20-40)
- Coeliac’s disease (transglutaminase)
- M:F 2:1
Pathophysiology
- Deposition of IgA in papillary dermis causing an immunological cascade
- Is an 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)
Signs & Symptoms
- ‘Suicidally itchy’ blisters and papules. Intensely pruritic
- Often few blisters as most are scratched and therefore appear as papules
- Intermittent cutaneous lesions mainly affecting the buttocks, knees and elbows
- Rraely any bowel symptoms of coeliac’s disease

Management
- Dapsone (antibacterial) – 50mg once daily
- Sulphapyridine (sulphonamide ABx)
- Betamethasone 0.05% – a potent topical steroid
References
- British Association of Dermatologists: Dermatology, a handbook for medical students & junior doctors
- bad.org.uk
- dermnetnz.org