How is it Diagnosed?
Dermatitis Herpetiformis (DH) is a chronic autoimmune blistering skin condition strongly
associated with gluten sensitivity and celiac disease. Diagnosis involves a combination
of clinical evaluation, histopathology, and immunological tests.
Patients typically present with intensely itchy, burning papulovesicular lesions
symmetrically distributed on extensor surfaces such as elbows, knees, buttocks, and
scalp. Despite the name, DH is not caused by the herpes virus.
Clinical suspicion leads to a skin biopsy taken from perilesional (adjacent, unaffected)
skin for direct immunofluorescence (DIF). This is the gold standard diagnostic test. DIF
reveals granular IgA deposits in the dermal papillae, which are highly specific for DH.
A second biopsy of the lesion itself may be examined under routine histopathology,
showing neutrophilic microabscesses at the tips of dermal papillae, though this is less
definitive than DIF.
Serologic testing for antibodies supports diagnosis and screens for associated celiac
disease. These include anti-tissue transglutaminase (tTG), anti-endomysial antibodies
(EMA), and anti-deamidated gliadin peptide (DGP) antibodies. A positive result confirms
gluten sensitivity.
Small intestinal biopsy, although more common in diagnosing celiac disease, may be
done in DH patients with significant gastrointestinal symptoms or unclear diagnosis. It
reveals villous atrophy and crypt hyperplasia.
Diagnosis is confirmed by clinical improvement following a gluten-free diet, though skin
lesions may take time to resolve. Dapsone may be prescribed for symptom control, but
long-term management requires strict dietary adherence.