Identify the type, prevalence and associated features of dermatological lesions in a cohort of RRMS patients treated with Fingolimod.

Fingolimod is considered a highly efficacious disease-modifying drug used in Relapse-Remitting Multiple Sclerosis (RRMS). According to the safety analysis in pivot trials of the drug, published in 2010, there is a possible but rare occurrence of skin cancer. Recently, anecdotal reports concerning non-neoplastic skin lesions associated to the immunosuppressive properties of Fingolimod have been published. Real-life cohort studies describing Fingolimod’s cutaneous adverse events are lacking.

Retrospective study of RRMS patients treated with Fingolimod who were followed in the MS clinic of the Neurology Department and in the Immunosuppression clinic of the Dermatology Department of the Coimbra’s Hospital, between 2012 and 2020.

We included 142 patients under Fingolimod who had at least one dermatological examination. Skin changes were considered neoplastic, infectious or inflammatory. Skin biopsies were performed in 17 patients. In terms of neoplastic disorders, we found one malignant melanoma in a 39-year-old man (0.7%), one squamous cell carcinoma (0.7%) and preneoplastic lesions – actinic keratosis (1 patient, 0.7%) and porokeratosis (1, 0.7%). Cancer-related lesions are not only more prevalent in this cohort but also occurred at an earlier age.

Viral infectious disorders are classically associated to immunosuppression: Human Papillomavirus (HPV) infection-related warts (7, 4.9%), genital condylomas (2, 1.4%), molluscum contagiosum (3, 2.1%), and recurrent herpetic vesicles of a limb (1, 0.7%). This type of lesions occurred independently of the previous treatment duration (2 to 12 years) but were not indication to therapeutic change in any patient. Pure inflammatory lesions – transient granulomatous panniculitis and cutaneous psoriasis - occurred in two patients (1.4%).

Both neoplastic, infectious and inflammatory skin disorders are prevalent in MS patients treated with Fingolimod. Early identification and treatment of these effects requires periodic dermatological evaluation.