Pemphigus herpetiformis with progression to pemphigus foliaceus: a case report.

Pemphigus herpetiformis (PH) is an uncommon variant of pemphigus that accounts for an estimated 6% to 7.2% of all cases of this skin disorder. The term pemphigus herpetiformis was coined by Jablonska et al. in 1975 to describe a entity that was clinically similar to dermatitis herpetiformis, showed acantholysis on biopsy, and responded to sulfapyridine. The authors considered that PH was a variant of pemphigus based on the direct immunofluorescence findings. PH typically presents with annular erythematous plaques, peripheral vesicles, and on occasions intense pruritus. Histologic features are highly variable and depend on the stage of the lesion. There have been reports of PH preceding or developing concurrently with pemphigus foliaceous (PF) or pemphigus vulgaris (PV). We present a case of PH that progressed to PF. The patient, a 34-year-old woman with no relevant past history, consulted for erythematous papules and plaques with peripheral vesicles and blisters on the lower extremities, the abdomen, and the scalp (Fig. 1). The lesions had been present for 3 months. There was no mucosal involvement. Two biopsies revealed different degrees of neutrophilic and eosinophilic spongiosis (Fig. 2A) and acantholysis, with the formation of intraepidermal vesicles (Fig. 2B). Several eosinophils were also observed in the papillary dermis. Direct immunofluorescence showed intercellular immunoglobulin (Ig) G and C3 deposits, predominantly in the suprabasal layers of the epidermis. Anti-epithelial antibodies (titer, 1:40) and anti-desmoglein 1 (Dsg1) antibodies were positive (175 IU/mL; normal value, < 20 IU/mL); the results for anti-Dsg1 antibodies were negative. A diagnosis of PH was made and treatment was started with prednisone 20 mg/d and topical clobetasol. The lesions improved, but 3 months later, erythematous scaling plaques started to reappear in the presternal, dorsal, and retroauricular areas and on the scalp (Fig. 3A). Biopsy of one of these plaques showed a subcorneal acantholytic vesicle (Fig. 3B). The anti-epithelial antibody titer was 1:80 and anti-Dsg1 antibody levels remained high at 161 IU/mL. Given the persistence of the lesions, treatment was started with dapsone 50 mg/d, with dose increments up to 100 mg/d. The clinical response was favorable and the dose was progressively reduced to 12.5 mg every second day. Occasional flares consisting of minimal papules with scaling on the neckline, back, and scalp were observed.