Abstract:

Fibrillary IgA deposits in the superficial dermis are a rare finding in the setting of dermatitis herpetiformis (DH). We report the case of a 52-year-old Pakistani man with a 3-year history of a pruritic, papulovesicular eruption on the posterior neck and back. Skin punch biopsy showed a subepidermal blister with papillary dermal neutrophilic infiltrate. Direct immunofluorescence (DIF) studies revealed fern-like deposition of IgA in the papillary dermis. IgG, IgM, C3 and fibrinogen, in addition to special stains for microorganisms, were negative. Fibrillary IgA deposits are identified as linear streaks in the superficial papillary dermis, in contrast to the more common granular IgA pattern reported in patients with DH. By electron microscopy, fibrillar deposits of IgA localize to microfibrils within dermal papillae. The fibrillar IgA pattern has been described in different demographic groups; although, a high prevalence is reported in Japanese patients with DH. Mixed fibrillar-granular patterns have also been detected. Fibrillar IgA deposition has been associated with atypical clinical presentations of DH (as seen in our patient), including atypical lesion morphology, and more generalized involvement of the trunk and limbs. A lack of circulating autoantibodies to tissue transglutaminase or endomysium, HLA-B8/DR3/DQ2 haplotype, and/or absence of gluten-sensitive enteropathy in some patients, suggests that the fibrillary IgA pattern may reflect a separate clinical-pathological subtype of the disease. However, the true molecular basis and biological significance of fibrillar pattern of IgA deposition on DIF studies in cases of DH remains to be determined.

Financial Disclosure:
No current or relevant financial relationships exist.

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Roman Drozdowski, BS