Dupilumab-induced enthesoarthritis and refractory atopic dermatitis successfully treated with baricitinib

Dear Editor, Cytokine inhibition through biological and targeted drugs has revolutionized the treatment of many chronic immune-mediated inflammatory diseases over the past 20 years. Although clinically effective and overall safe, the therapeutic manipulation of the cytokine system may trigger immune side-effects in a small, albeit not negligible, proportion of patients. This is the case, for instance, of TNF inhibitors (TNFi), which have been associated with the development of lupus autoimmunity and paradoxical psoriasis through IFN over-production [1]. Immune side-effects were also described for dupilumab, the first biological drug approved for atopic dermatitis (AD), which inhibits IL-4 and IL-13 signalling. In addition to the appearance of psoriasis, some authors have indeed reported the development of seronegative chronic synovitis and enthesitis in AD patients treated with dupilumab, and real-life data found immune-mediated enthesitis/arthritis in up 6% of the patients [2]. Inflammatory arthritis occurred early, within a few...