Ixekizumab as a successful treatment in pediatric generalized pustular psoriasis

Background: Generalized Pustular Psoriasis (GPP) is an autoinflammatory, multisystemic disease, characterized by widespread eruption of neutrophilic pustules on erythematous base, accompanied by systemic symptoms such as fever, leukocytosis, arthralgia, and general malaise. Globally, the disease is rare, particularly in children. If not adequately diagnosed and treated, systemic inflammation and multiorgan involvement can be life-threatening. The pathogenesis of GPP mainly involves the innate immune system, with inflammatory processes and neutrophil activation driven primarily by IL-36, but also by IL-1, TNF-alpha, IL-17 A. In particular, IL-17 A acts as a potent inducer of neutrophil recruitment. We report the case of a 7-years-old girl with GPP successfully treated with Ixekizumab, an IL-17 A antagonist. Case presentation: A 7-years-old girl with an history of plaque psoriasis came to our attention for the sudden appearance of erythematous patches surmounted by pustules on the trunk and lower limbs, following repeated episodes of purulent tonsillitis. We started therapy with cyclosporine at a dosage of 3,5 mg/kg/day, with no clinical benefit and progression of manifestations to a sub-erythrodermic state after 2 weeks. Blood tests showed neutrophilic leukocytosis, and the patient experienced hyperpyrexia and malaise. Since ixekizumab was recently approved for pediatric use in patients with moderate to severe plaque psoriasis, we started therapy with 80 mg Ixekizumab, combined with prednisone at a dosage of 12.5 mg/day, gradually tapered until discontinuation after 15 days. A second dose of Ixekizumab 40 mg was administered at week-4, according to the indication of ixekizumab in pediatric plaque psoriasis. At week-8 the patient achieved complete remission of skin manifestations and normalization of blood count. After achieving a stable remission, at week 36 we decided to increase the administration interval to 6 weeks. The patient is still on therapy with ixekizumab 40 mg every 6 weeks, maintaining complete remission during a 52-week follow-up, without safety concerns. Conclusions: This report supports the use of ixekizumab as a safe and effective option, both in the short and long-term, in the treatment of GPP, even at pediatric age. Larger studies are needed to confirm this positive, real-life experience.