The class of medications known as Janus kinase inhibitors block cytokine-mediated signaling via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, which plays an important role in immunoregulation and normal cell growth. This class includes the drugs tofacitinib, approved for the treatment of rheumatoid arthritis, and ruxolitinib, approved for the treatment of myelofibrosis and polycythemia rubra vera. The most common adverse events (AEs) reported in patients taking tofacitinib are infections, whereas the most common AEs in patients taking ruxolitinib are anemia and thrombocytopenia. Both first and second generation Janus kinase inhibitors have become promising treatment modalities for dermatologic conditions such as psoriasis, atopic dermatitis, alopecia areata, vilitigo, dermatomyositis, and graft-versus-host disease. Future promising areas of investigation include treatment of cutaneous lupus, cutaneous T-cell lymphoma, melanoma, allergic contact dermatitis, and lichen planus.
Keywords: Janus kinase inhibitors; JAK inhibitors; JAK-STAT pathway; tofacitinib; ruxolitinib; alopecia areata; atopic dermatitis; dermatomyositis; graft-versus-host disease; psoriasis; vitiligo.