Dermatitis Herpatiformis Flashcards
What is dermatitis herpetiformis (DH)?
A chronic, intensely pruritic, blistering skin condition associated with gluten sensitivity and celiac disease.
What causes dermatitis herpetiformis?
Gluten sensitivity leading to IgA deposition in the dermal papillae.
What role does gluten play in DH?
Gluten ingestion triggers an immune response, leading to IgA antibody formation against epidermal transglutaminase.
What is the primary antigen in DH?
Epidermal transglutaminase (TG3), distinct from tissue transglutaminase (TG2) involved in celiac disease.
What genetics are linked to DH?
DH can be linked to HLA-DQ2 and HLA DQ8
What are the characteristic symptoms of dermatitis herpetiformis?
Intense pruritus and burning, with symmetrical vesicles and papules on extensor surfaces.
Where on the body does DH typically present?
Elbows, knees, buttocks, lower back, and scalp.
What gastrointestinal condition is almost universally associated with DH?
Celiac disease, even if asymptomatic.
What other autoimmune conditions may be associated with DH?
Thyroid disorders, type 1 diabetes, and pernicious anemia.
How is dermatitis herpetiformis diagnosed?
Skin biopsy with direct immunofluorescence showing granular IgA deposits in the dermal papillae.
What serologic tests are useful in DH?
Anti-tissue transglutaminase (tTG) and anti-endomysial antibodies (EMA).
Is an intestinal biopsy required for diagnosis?
Not always, but small bowel biopsy can confirm celiac disease if serology is unclear.
What is the cornerstone of treatment for dermatitis herpetiformis?
A strict lifelong gluten-free diet to reduce skin lesions and prevent intestinal damage.
What medication provides rapid symptom relief in DH?
Dapsone, which reduces inflammation and itching within days.
What are the potential side effects of dapsone?
Hemolysis (especially in G6PD deficiency), methemoglobinemia, and peripheral neuropathy.
