Atypical Follicular-Pigmentary Variant of Hailey-Hailey Disease: A Diagnostic Dilemma.

Hailey-Hailey disease (HHD) is a rare autosomal dominant acantholytic dermatosis characterized by recurrent erosive plaques in intertriginous areas. Atypical presentations can resemble other acantholytic disorders, making diagnosis challenging. A 38-year-old male presented with recurrent pruritic lesions over flexural regions, worsened by heat and sweating. Although classical erosive plaques were noted over the neck and axillae, lesions over the groin and other flexures showed a predominant papular and follicular morphology with marked post-inflammatory pigmentation, mimicking other acantholytic dermatoses. Histopathology revealed suprabasal acantholysis with a "dilapidated brick wall" pattern. Clinicopathological correlation established the diagnosis of HHD. Atypical papular forms of HHD may mimic other acantholytic dermatoses, complicating diagnosis. Recognition of such morphological variation and clinicopathological correlation is essential for accurate diagnosis.