Presenter: Risa Gorin, D.O.

Dermatology Program: St. Barnabas Hospital Dermatology Department, Bronx, New York

Program Director: Cindy Hoffman, DO, FAOCD

Submitted on: May 29, 2007

CHIEF COMPLAINT:  Unilateral Hyperpigmented Axillary Eruption

CLINICAL HISTORY: A 71-year-old Hispanic female with a past medical history of insulin-dependent diabetes, and left cerebral vascular accident was referred by her primary care physician for evaluation of a unilateral, hyperpigmented rash located in the right axilla. According to the patient the rash had been present for three weeks. She admitted to using copious amounts of deodorants in the area. The patient denied any symptoms of pruritus or burning. Prior to the presentation, she did not receive any treatment for her rash.

PHYSICAL EXAM:
Cutaneous examination revealed multiple hyperpigmented papules coalescing into a velvety plaque in a linear distribution in the right axilla. No active lesions were noted in the left axilla. Due to her past history of a left-sided stroke, the patient was noted to have difficulty raising her right axilla.

LABORATORY TESTS:

A 3-mm punch biopsy of a right axillary lesion was performed. The patient was asked to discontinue deodorant use and replaced it with the bacitracin ointment bid to the biopsy site.

DERMATOHISTOPATHOLOGY:

Microscopic evaluation revealed severe compact parakeratosis with retention of keratohyalin granules throughout the stratum corneum.

DIFFERENTIAL DIAGNOSIS:

1.   Unilateral acanthosis nigricans
2.   Axillary granular parakeratosis
3.   Post-inflammatory hyperpigmentation
4.   Linear epidermal nevi
5.   Contact dermatitis