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.