Cutaneous side effects are observed in 46-62% of patients on checkpoint inhibitor therapy and occur after a median of 2-3 weeks, but also up to two years after the start of immunotherapy. Rash, pruritus, and vitiligo-like lesions are the most common; lichenoid reactions, blistering reactions, psoriasis, and sarcoid-like lesions are less common. In 90% of cases, cutaneous irAE are mild and can be treated with topical therapy. Serious and potentially fatal cutaneous adverse events include DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms), Stevens-Johnsons Syndrome, toxic epidermal necrolysis, bullous skin lesions, and dermatitis herpetiformis (Heinzerling et. al, Dtsch Arztebl, 2019; Belum et. al., Eur J Cancer, 2016). The literature on erythema multiforme under immunotherapy is limited to individual case reports. Cases have been reported with ipilimumab, nivolumab and pembrolizumab. Treatment was mostly with systemic steroids, in one case also with IVIG. EM often led to discontinuation of immunotherapy (Zimmer, L et al, J Transl. Med, 2015; Jour et. al., J Cutan Pathol., 2016; Sundaresan et. al., Dermatol Online J., 2017; Utsunomiya et. al., Case Rep Dermatol., 2018; Yano et. al., Trends in Immunotherapy, 2021; Hashimoto et al, J Clin Med., 2021; Ambur et. al., Cureus, 2021).