Ιmmune checkpoint inhibitors (ICIs) have revolutionized the management of advanced cancers. Nevertheless, the oncologic response is often achieved at the cost of immune-related adverse events (irAEs). We present a case of an immune-mediated lichen planus (LP) and a literature review of similar cases. A 60-year-old man, who is being treated with pembrolizumab for a pulmonary giant cell carcinoma since April 2022, presented in November 2022 with a pruritic eruption that appeared two weeks ago. Examination showed bright purple confluent scaly papules on wrists, proximity of limbs, back and buttocks and palmar keratoderma made of violaceus papules covered with reticular white striae. Histological examination revealed an epidermal hyperplasia, vacuolization of the basal layer, necrotic keratinocytes and a band-like subepidermal lymphocytic infiltrate with many eosinophils. The diagnosis of an immune-related LP was retained. Pembrolizumab was withheld because of the severity and the extension of the lesions. Superpotent topical steroids were prescribed with a significant improvement of the rash within 3 weeks. Immune-mediated lichenoid euptions represent one of the most frequent dermatologic irAEs. In our patient, the onset seven months after the initiation of ICIs, the infiltrate rich in eosinophils, and the rapidly diffused character are indications of an immuno-mediated LP.

Since pemphigus blisters are intraepidermal, scarring should induce at most a post-inflammatory hyperpigmentation. We describe a very atypical and unusual course of pemphigus vulgaris with extensive keloid formation despite high systemic steroids. This could be promoted by the severe flare of the disease, the delay of scarring and the superinfection.

Although lungs represent the main target of the SARS-CoV2, the novel virus may affect other tissues. In the pandemic context, unexplained cutaneous ischemic lesions would be suggestive of the infection and should draw attention to a serious course of the disease.

Confluent and reticulated papillomatosis (CRP) is a rare skin condition of uncertain etiology. The anti-bacterial and most importantly the anti-inflammatory mechanisms of some antibiotics seem to explain the effectiveness of these medications. Other measures such as reducing weight and treating an underlying endocrine disorder may be helpful.