The FP initially treated the area with topical ketoconazole cream, which stung, but partially improved the patient’s symptoms. Because the rash persisted, the FP performed a punch biopsy, which showed widespread epidermal acantholysis or separation of epidermal cells. This is a hallmark of pemphigus vulgaris and benign familial pemphigus (Hailey-Hailey disease).
Hailey-Hailey disease is an uncommon autosomal dominant inherited blistering disorder that affects connecting proteins in the epidermis, which is why histology overlaps with pemphigus. Symptoms may not present until the second or third decade of life and often occur in flexural or high friction areas, including the axilla and inguinal folds. Any skin injury may trigger a flare, including sunburn, infections, heavy sweating, or friction from clothes. Bacterial overgrowth or colonization can cause a bad odor and social isolation in severe cases.
The differential diagnosis of axillary skin disorders is broad and includes irritant contact dermatitis, contact dermatitis, seborrheic dermatitis, hidradenitis suppurativa, candida intertrigo, and psoriasis. Clinical clues that favor Hailey-Hailey disease include fragile vesicles or pustules at the periphery and small focal erosions. The family history is helpful but not always known.
Some patients require topical therapy sequentially, in combination, or personalized through trial and error that addresses the inflammation, bacterial overgrowth, and fungal disease. Patients also may require long-term doxycycline therapy to suppress flares. Most patients will benefit from at least prn use of topical steroids for inflammation. Addressing sweating with topical aluminum chloride or botulinum injections can be beneficial. Low dose naltrexone, as well as afamelanotide, has shown promise in a few small case series.
The patient in this case improved with topical triamcinolone 0.1% ointment bid and systemic doxycycline 100 mg bid for 2 weeks. However, he continued to require occasional rounds of oral doxycycline with flares.
Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained).