Systemic methotrexate for prurigo nodularis and keratoacanthomas in actinically damaged skin

INTRODUCTION We previously reported a cohort of elderly patients with concurrent development of debilitating prurigo nodularis, extreme and disabling pruritus with or without eczematous dermatitis, and keratoacanthomas in the presence of actinic damage. This report is a long-term follow through on patients who were successfully transitioned from cyclosporine, acitretin, and topical 5-fluorouracil to subcutaneously administered methotrexate. We believe that an underlying dysregulation of both inflammatory and cell growth pathways predisposes these individuals to the development of both types of lesions. Three of the patients have since been successfully treated with systemic methotrexate and are described below. We stated in our original report that no patients had keratoacanthomas while on cyclosporine and acitretin; however, in reviewing the material for this follow-up report, keratoacanthomas were noted in the patients’ files. These lesions were existing lesions that did not clear after the initiation of therapy and were deemed suspicious enough for further evaluation. Herein we describe patients who underwent transition from cyclosporine to methotrexate and experienced relief of their symptoms. Traditional treatment options for keratoacanthomas include standard excision,Mohsmicrographic surgery, systemic retinoids, radiotherapy, curettage and electrodessication, and intralesional 5-fluorouracil. In patients with a predisposition to the development of pruritic nodules and multiple keratoacanthomas, many of the aforementioned treatments are ineffective or only elicit some clinical response, often with relapse.