Successful Treatment of Two Rare Pediatric Keratinization Disorders with Secukinumab: Epidermolytic Ichthyosis and PRP–GPP Overlap

Qianyue Xu,1– 3 Jia Zhang1– 3 1Dermatology Center, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 2Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 3Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of ChinaCorrespondence: Jia Zhang, Dermatology Center, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, People’s Republic of China, Email [email protected]: Pediatric erythroderma can arise from either inherited keratin defects or cytokine-driven inflammation, yet evidence for biologic therapies in these settings is limited. We report two rare pediatric cases successfully treated with secukinumab, an IL17A–targeted monoclonal antibody: (i) a 2-year-old boy with genetically confirmed epidermolytic ichthyosis (EI, KRT10 mutation:c.467G>A, p.Arg156His) refractory to conventional care, who achieved > 60% improvement in erythema and scaling one week after a single off-label 150 mg subcutaneous secukinumab dose, with remission maintained for 12 months on monthly dosing; and (ii) an 11-year-old girl with coexistent Type III (juvenile) pityriasis rubra pilaris and acute generalized pustular psoriasis (PRP–GPP overlap) unresponsive to acitretin and methotrexate, who attained complete remission for 12 months following standard secukinumab induction (300mg weekly × 5) and maintenance every four weeks. These cases extend the potential utility of IL17A blockade beyond psoriasis vulgaris to both structural keratinopathies and inflammatory pustular dermatoses in children. While limited by the nature of a two-patient case series, these findings warrant prospective studies to clarify optimal dosing and long-term safety of IL-17A blockade in pediatric dermatology.Plain Language Summary: In this report, we describe (1) a two-year-old boy with a keratin 10 mutation causing epidermolytic ichthyosis, and (2) an eleven-year-old girl with a unique overlap of pityriasis rubra pilaris and generalized pustular psoriasis. Both children achieved rapid and sustained remission of their debilitating skin disease after off-label treatment with secukinumab, despite having failed conventional therapies. To the best of our knowledge, Case 1 is the first reported Chinese EI patient to respond to secukinumab, and Case 2 is the first case of concurrent GPP and PRP achieving remission with IL-17A blockade. The innovative aspect of our work lies in extending IL-17A blockade beyond its traditional use in psoriasis vulgaris to rare disorders of keratinization and autoinflammatory skin disease. We believe this demonstrates a novel therapeutic strategy and provides hope for patients with otherwise refractory pediatric dermatoses. Keywords: epidermolytic ichthyosis, KRT10, pityriasis rubra pilaris, generalized pustular psoriasis, secukinumab, pediatric dermatology