33521 Two cases of oral baricitinib associated papular eruption on face

Abstract

Background: Janus kinase (JAK) inhibitors reduce inflammation by interrupting JAK-STAT pathway and are used for various disease. However, cutaneous adverse effects including reactivation of herpes simplex virus, herpes zoster, disseminated molluscum contagiosum, and acneiform eruptions were reported. In addition, few cases of granulomatous inflammation after JAK inhibitor use have been reported recently. Methods: Patient 1, a 40-year-old woman, presented with erythematous papules on periorbital and perioral area for 13 months. She had been taking prednisolone and hydroxychloroquine for rheumatoid arthritis (RA) for 1 year, but symptoms were not controlled. Thus, oral baricitinib was administered. After 2 months, facial lesions appeared. Patient 2, a 64-year-old woman, presented with erythematous papules on face developed 2 weeks ago. She has been taking baricitinib for RA because of inadequate response to methotrexate. Facial eruption occurred 4 months after initiation of baricitinib. Results: For patient 1, histopathologic examination showed dense dermal infiltration of lymphocytes, histiocyte and few plasma cells, which implicated granulomatous dermatitis. Doxycycline and topical gentamycin/prednicarbate were given and the lesions showed response. Patient 2 showed improvement after treatment with doxycycline, topical metronidazole, and topical ivermectin. However, lesions aggravated 7 months after doxycycline cessation with continuous baricitinib use. Conclusion: Although JAK inhibitors are known to be effective for the treatment of granulomatous diseases like sarcoidosis, granulomatous drug eruption has been reported. In our cases, facial skin lesions appeared 2 and 4 months after starting baricitinib, respectively. Our cases imply that dermatologists should be aware of the potential association between JAK inhibitors and cutaneous eruption.