Pityriasis Rubra Pilaris - a difficult path to optimal treatment. Case report.

Pityriasis Rubra Pilaris is a rare, chronic inflammatory dermatosis of unknown etiology, presenting with erythema and papular eruptions. Treatment is difficult due to the lack of causal therapy, guidelines and requires an individualized approach. The most common treatments are systemic retinoids, immunosuppressants, phototherapy and biological therapy. This article presents the case of a 73-year-old man suffering from type 1 pityriasis rubra pilaris. The patient was initially treated with acitretin, which was discontinued due to hypogammaglobulinemia. This rare side effect of acitretin has not been previously published. As a second-line treatment, the patient received methotrexate, but with no clinical improvement after 3 months and an increase in skin pruritus. Finally, the use of isotretinoin resulted in significant clinical improvement and was well tolerated.