LAUSR

documenting strong expression of IL-17A in the lesional epidermis of patients with pustular psoriasis. However, the results of the above-mentioned trials must be interpreted with caution, as both were designed as uncontrolled, openlabel studies. In addition, allowance of concomitant systemic therapy with acitretin or methotrexate further complicated the objective interpretation of treatment efficacy. Thus, there is an urgent need to confirm these observations in a more valid, and objective way, ideally, in randomized controlled trials. The current study also revealed another gap in managing patients with GPP, namely the lack of a widely accepted and valid method of severity assessment. Both study groups used PASI (Psoriasis Area and Severity Index) as a GPP assessment tool. However, this instrument, despite being widely used in plaque-type psoriasis, is not well suited for the evaluation of the pustular skin lesions present in GPP. Unless a valid GPP severity scale is developed, it will remain difficult to reliably analyse GPP treatment efficacy. In addition, a single, validated GPP severity-assessment tool would also facilitate comparison of various treatment modalities in GPP across different trials. Finally, it should be emphasized that the follow-up period after treatment cessation in the Yamasaki et al. study was short, not allowing for the proper assessment of risk of disease recurrence. This is particularly important, as recently indicated by Khemis et al., who reported that patients who stopped brodalumab therapy may experience severe psoriasis rebound, even developing GPP while having had plaquetype psoriasis prior to the treatment. It is currently unclear whether risk of a rebound phenomenon is also true for brodalumab-treated patients with GPP or psoriatic erythroderma. Despite the above-mentioned limitations, the study by Yamasaki et al. is an important step forward, as one of very few published studies analysing the efficacy of biological therapy in GPP and psoriatic erythroderma and providing solid evidence of a very high response rate to brodalumab treatment. Thus, having this new compound on the market will give our severely ill patients a better chance for complete skin lesion clearance and a return to a normal life.