Acrodermatitis continua of Hallopeau (ACH) is a rare chronic inflammatory skin disease. Treatment is extremely challenging and mostly based on empirics as there is only scarce evidence from case reports and few small case series. In this retrospective study, patients with ACH treated at five university medical centers were analyzed according to patient and disease characteristics and treatment experience. We identified 39 patients with ACH with a mean age of 54.4 years at onset, of whom 22 (56.4%) were female. A total of 115 systemic treatment courses were analyzed with methotrexate as the most common therapy (27.0%). Overall, effectiveness of systemic treatments was low (excellent response rate: 14.8%). Among non‐biologics, excellent response was noted in 21.1% (4/19) of treatment courses with methotrexate, followed by acitretin (13.3%; 2/15). Among biologics, guselkumab (excellent response: 100%; 2/2), secukinumab (excellent response: 42.9%; 3/7) and adalimumab (excellent response: 20.0%; 2/10) were most efficacious. The median drug survival was 7.0 months and did not differ significantly between the subgroup of non‐biologic and biologic therapies. To our knowledge, this is the largest case series in ACH investigating patient characteristics and treatment outcomes. Based on our treatment experience, we suggest a treatment algorithm starting with acitretin or methotrexate as first‐line therapy, followed by biologics. Cyclosporin may be used for short‐term control. However, none of the applied systemic therapies yielded satisfying efficacy in our cohort. In patients with primary non‐response, switch of treatment should be evaluated timely on an individual basis, considering possible irreversible disease complications such as nail loss. More research with prospective design is needed to further evaluate traditional and also particularly newer antipsoriatic drugs in ACH.

Generalized pustular psoriasis (GPP) is a rare, potentially life-threatening inflammatory skin disease. Our aim was to assess patient and disease characteristics and analyze drug survival rates in the treatment of GPP in a real-life setting. In this retrospective study, 201 treatment series of 86 patients with GPP treated at five University Medical Centers were analyzed. Overall, excellent response was reached in 41.3% of all treatment courses, partial response in 31.4%, and nonresponse in 27.3%. Biological treatment was significantly more effective than non-biological therapies (excellent response: 47.4% vs 35.9%; P = .02). Overall, the median drug survival was 14.0 months (biologicals: 36.0 months vs nonbiologicals: 6.0 months; P < .001). The crude probability of survival was highest for secukinumab (hazard ratio [HR] of drug discontinuation compared with acitretin: 0.22), followed by ixekizumab and ustekinumab (HR: 0.38 each), adalimumab (HR: 0.59), etanercept (HR: 0.62), infliximab (HR: 0.69), cyclosporine (HR: 1.00), acitretin (reference for HR), fumaric acid esters (HR: 1.06), methotrexate (HR: 1.26), and apremilast (HR: 3.44); no drug discontinuation with guselkumab. Our results reveal high efficacy and drug survival, particularly for IL-17 and IL-(12)/23 antagonists. Thus, these biologics may be considered early in the therapeutic algorithm of GPP.

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