C. Pruritus
Pruritus is one of the most common adverse skin responses with immune checkpoint inhibitors. Pruritus can present with or without a rash and patients may have skin changes i.e. erosions, ulcerations, nodules secondary to pruritus 58.
Pathogenesis: The pathophysiological mechanism for these cutaneous manifestations is not fully known, but it includes CD4+ and CD8+T-cells which are likely activated by the anti-PD-1/PD-L1 immunotherapy target an antigen present in the epidermis or dermis61.
Clinical incidence: A total of three cases were reported with pruritus reactions. Two cases were reported with pembrolizumab22, 62, and one with nivolumab61 therapy. Grade I pruritus includes mild symptoms with the localized distribution, whereas Grade II pruritus causes irregular, intense symptoms with persistent skin changes or intermittent widespread distribution. Grade III and grade IV pruritus are most adverse with widespread constant distribution, intense indications with persistent skin changes that interfere with sleep patterns 58.
Treatment: For grade III and grade IV pruritus, treatment was initiated with systemic steroids methylprednisone or oral prednisolone (0.5-1 mg/kg/day) with persistent immunotherapy while other managements include cyclosporine 22. Treatment of pruritus also includes narrowband UVB therapy 61.
Autoimmune skin disorders
PD-1/PD-L1 signaling pathway involves the pathophysiology of numerous autoimmune skin diseases. Moreover, these monoclonal antibodies can also induce the progression of de novo autoimmune cutaneous diseases like bullous pemphigoid, psoriasis, vasculitis, and dermatomyositis.