Eruptive Seborrheic Keratoses Following Hpv Vaccination During Ixekizumab Therapy for Psoriasis: A Case Report and Literature Review.

Psoriasis is a chronic, recurrent, inflammatory autoimmune skin disease. The advent of biologics, such as ixekizumab, has provided a breakthrough for patients with moderate-to-severe disease by specifically inhibiting the interleukin-17A (IL-17A) mediated inflammatory cascade. The human papillomavirus (HPV) vaccine is a cornerstone in the prevention of HPV-associated malignancies, with well-established safety and efficacy profiles. However, due to the unique immune status of patients with psoriasis, cutaneous adverse events following HPV vaccination during biologic therapy have rarely been reported. Seborrheic keratosis (SK) is a common benign epidermal tumour. Its eruptive variant, known as the Leser-Trélat sign, has traditionally been associated with internal malignancies; however, recent studies suggest potential links to inflammation, pharmacological agents, and immune alterations. We report the case of a 37-year-old female with psoriasis who, after achieving stable disease control on ixekizumab, developed widespread eruptive brown macules, patches, and papules within one month of receiving a quadrivalent HPV vaccine. Histopathological examination confirmed SK, and malignancy, as well as other associated disorders, were excluded. The lesions faded following oral acitretin therapy. This case highlights the possibility that ixekizumab in combination with HPV vaccination may synergistically alter immune homeostasis, thereby precipitating eruptive SK. We discuss potential mechanisms, propose clinical management considerations, and provide insights that may inform future research and clinical practice. The ultimate aim is to contribute to the refinement of guidelines on vaccination in patients receiving biologic therapy for psoriasis, ensuring both therapeutic efficacy and patient safety.