Anti-PD1/PDL1 induced psoriasis

Immune checkpoint inhibitors are novel agents approved for the treatment of late-stage malignancies. Despite its important clinical benefits, checkpoint inhibition is associated with a unique spectrum of side effects known as immune-related adverse events. Skin toxicities are the most frequent immune-related adverse events during anti-PD1 blockade therapies. Among them, rare cases of psoriasis exacerbation have been reported.We present the clinical characteristics of exacerbated psoriasis in 5 patients under anti-PD1/PDL1 therapy.A total of 5 patients were overall included (4 males, 1 female mean age 65.8 years). Among them, 3 were diagnosed with nonsmall cell lung cancer, 1 with papillary urothelial carcinoma, and 1 with squamous cell carcinoma of the tonsil. Of all, 3 patients were treated with anti-PD1 (1 with pembrolizumab, 2 with nivolumab), whereas the remaining 2 with anti-PDL1 (durvalumab). Only 1 out of 5 patients had active psoriatic lesions at the time of treatment initiation, 2 shared a past history of psoriasis, and 1 reported a strong related family history (3/5 siblings). Four out of 5 patients experienced guttate lesions, though the most severe exacerbation was noted in the durvalumab group. Four out of 5 patients managed to continue treatment after close dermatologic monitoring, whereas 1 patient under durvalumab was forced to treatment delays owing to the severity of the skin reactions. Skin rashes appeared in all patients after the fourth cycle of immunotherapy.Both anti-PD1 and anti-PDL1 therapies can lead to psoriasis exacerbation although more severe flares were noted in patients treated with durvalumab. Not only personal but also related family history of psoriasis are significant risk factors and need to be outlined before treatment initiation. If such related history exists, strict skin surveillance can lead to the early diagnosis and treatment of any psoriatic exacerbations that could otherwise severely affect quality of life or even compromise therapeutic protocols and final prognosis.