BH20 An unintended sequela of hair regrowth: severe Janus kinase inhibitor-associated acneiform eruption in alopecia areata

Abstract

A 30-year-old woman with a 14-year history of alopecia areata presented with worsening hair loss. Her medical history included anxiety, depression, asthma and mild acne previously treated with lymecycline and topical therapies. Following the initial diagnosis, she experienced spontaneous hair regrowth; however, over the subsequent 4 years, the alopecia persisted despite topical and intralesional corticosteroid treatment, with intermittent regrowth followed by relapse in new areas. She had a Severity of Alopecia Tool (SALT) score of 51, and ritlecitinib 50 mg once daily was initiated in 2024. After 6 months, there was marked clinical improvement, with a reduction in SALT score to 3. However, she developed an inflammatory acneiform eruption characterized by crusted erythematous plaques on the cheeks, with papules and pustules involving the central forehead, cheeks and chin. This was associated with facial swelling and myalgia. Investigations, including full blood count, renal and liver function tests and bacterial skin swabs, were unremarkable. Initial management included a 6-week tapering course of oral prednisolone (starting at 30 mg daily) and a 3-month course of trimethoprim 300 mg twice daily. Despite treatment, the acneiform eruption persisted, and ritlecitinib was discontinued 8 months after initiation. Oral isotretinoin 40 mg once daily was commenced, with the addition of erythromycin 500 mg twice daily for 4 weeks due to ongoing inflammation. Six months after ritlecitinib discontinuation, the patient experienced significant relapse of alopecia areata with a SALT score of 26. While the acneiform eruption largely resolved, persistent facial erythema with flushing remained. The disease course had a substantial negative impact on the patient’s mental health. This case highlights JAK inhibitor-associated acneiform eruption as an important and potentially treatment-limiting adverse event, even in the context of successful hair regrowth. The authors have received sponsorship and remuneration from Pfizer for educational and consultancy work, unrelated to this work.