Successful treatment of refractory classic juvenile pityriasis rubra pilaris with adalimumab in a 4-year-old girl: a case report.

Background: Classic juvenile pityriasis rubra pilaris (PRP) (Griffiths type III) is a rare inflammatory papulosquamous dermatosis that is often refractory to conventional topical and systemic treatments. Despite the growing use of tumor necrosis factor-α (TNF-α) inhibitors in adult PRP, clinical evidence for their efficacy and safety in children under 5 years remains extremely limited. Case presentation: We herein report a 4-year-and-7-month-old Chinese girl presenting with a 20-day history of rapidly progressive generalized erythema, follicular keratotic papules, diffuse scaling, severe palmoplantar keratoderma and intractable pruritus. Initial differential diagnoses included psoriasis and pityriasis rubra pilaris (PRP), and skin histopathology confirmed classic juvenile PRP. Prior interventions with topical corticosteroids, emollients, oral antihistamines and traditional Chinese medicine yielded minimal clinical improvement. From the caregiver's perspective, persistent extensive cutaneous lesions with unremitting pruritus disrupted the child's daily activities, and multiple unsuccessful conventional therapies triggered considerable anxiety regarding long-term disease management. Given disease refractoriness, off-label adalimumab therapy was initiated. The patient received subcutaneous adalimumab at an initial dose of 20 mg at week 0, followed by 20 mg at week 1, and subsequent maintenance doses of 20 mg every two weeks, with a total of 8 injections. Approximately 3 months after treatment initiation, all cutaneous lesions achieved complete resolution, with only residual hypopigmented macules observed. No severe adverse events occurred during the treatment course. At the latest follow-up, 8 months after the final adalimumab injection, the patient maintained sustained complete remission without relapse. Conclusion: This clinical case demonstrates that adalimumab achieves rapid therapeutic efficacy and favorable short-term safety in young children with refractory classic juvenile PRP. Our findings support the potential role of TNF-α inhibitors as an effective alternative for severe pediatric PRP unresponsive to conventional therapies. Further prospective controlled trials are warranted to validate the long-term safety profile and optimize the dosage regimen for young pediatric populations.