ANN R.CUSACKMDSENAIT W.DYSONMDJACQUELINE M.JUNKINS-HOPKINSMDVINCENTLIUMDKARLA S.ROSENMANMD
Findings from a skin biopsy specimen showed hyperkeratosis and parakeratosis, with retention of keratohyaline granules in the stratum corneum. The papillary dermis displayed a perivascular lymphohistiocytic infiltrate (Figure 2). The patient was treated with topical hydrocortisone acetate cream, 1%, with complete resolution of the eruption after 1 week.
In 1991, Northcutt et al1 described 4 patients with a well-demarcated axillary eruption that was clinically similar to Hailey-Hailey disease yet displayed unusual parakeratosis on biopsy. Mehregan et al2 described a similar eruption 4 years later. Granular parakeratosis is a hyperpigmented, hyperkeratotic eruption of plaques and papules of unknown etiology that predominantly occurs in middle-aged women. Most often pruritic, these friable lesions are typically confined to the axilla yet may rarely appear in areas such as the groin, inframammary region, and abdomen.3 Although the etiology is yet unknown, this condition may represent a contact reactionto an antiperspirant or deodorant in conjunction with potentiating factors such as chemical and mechanical irritation and a moist environment.2- 4 The clinical differential diagnosis is broad and may include entities such as Hailey-Hailey disease, pemphigus vegetans, acanthosis nigricans, and dermatophytosis.3
Unilateral Pruritic Axillary Rash—Diagnosis. Arch Dermatol. 2008;144(12):1651-1656. doi:10.1001/archderm.144.12.1652-b