Prurigo nodularis and pembrolizumab: A therapeutic challenge

Immune checkpoint inhibitor-induced cutaneous toxicities: a review of histopathologic and clinical features

Immune checkpoint inhibitors (ICIs) represent an emerging treatment option for a variety of cancer types. Through inhibition of programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1), and/or cytotoxic lymphocyte-associated antigen-4 (CTLA-4), ICIs activate the host's immune system causing a heightened anti-tumor response. However, off-target effects of ICIs can result in numerous different immune-related cutaneous adverse events (irCAEs). Beyond impacting quality of life, irCAEs can lead to dose limitations or discontinuation of anti-cancer therapies. Correct diagnosis is necessary for expedient and appropriate management. Skin biopsies are often performed to increase diagnostic accuracy and guide clinical management. An extensive literature review was performed using the PubMed database to identify the reported clinical and histopathologic features of irCAEs. This comprehensive review primarily details the histopathologic features of various irCAEs reported to date. Clinical presentation and immunopathogenesis are also discussed in relation to histopathology.

Cutaneous Adverse Reactions of Immunotherapy in Patients with Advanced Melanoma

Immune checkpoint blockers (ICBs) have been widely used during the last decade for the treatment of various tumors, including advanced and metastatic melanoma. While these agents have improved melanoma patients’ survival rates, they have also been associated with various autoimmune toxicities, with the skin being most commonly affected. The severity of cutaneous toxicity can not only negatively affect patients’ quality of life but can also limit the proper treatment of cancer. Thus, the role of the dermatologist is substantial in early detecting and promptly treating these adverse events. Maculopapular rash, psoriasiform, lichenoid dermatoses and bullous pemphigoid are the most frequent cutaneous adverse events that require immediate intervention. Other rare autoimmune toxicities, e.g., sarcoidosis, dermatomyositis or subacute lupus, have also been reported. In this review, we summarize the aspects of ICB-induced cutaneous toxicities in patients with melanoma, emphasizing their management and treatment options in clinical practice.

Diagnostic Workup and Evaluation of Patients with Prurigo Nodularis

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized oftentimes by symmetrically distributed, severely pruritic nodules. Currently, the pathophysiology of PN remains to be fully elucidated, but emerging evidence suggests that neuroimmune alterations play principal roles in the pathogenesis of PN. There are several associated etiologic factors thought to be associated with PN, including dermatoses, systemic, infectious, psychiatric, and neurologic conditions. We conducted a systematic literature review to evaluate the clinical presentation, diagnosis, and etiologic factors of PN. In this review, we discuss common differential diagnoses of PN and recommend an evidence-based, standardized diagnostic evaluation for those with suspected PN.