This Primer by Guttman-Yassky and colleagues reviews the epidemiology, pathophysiology, diagnosis and treatment of alopecia areata. This Primer also discusses the quality of life issues faced by patients and future research avenues.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the respiratory pathogen that caused the coronavirus disease 2019 (COVID-19) pandemic. In this Primer, Sherman et al. focus on the acute stage of SARS-CoV-2 infection, describing its epidemiology and pathogenesis, discussing its diagnosis and management, and summarizing effects on quality of life as well as areas for further research.

In this Primer, Plikus and colleagues review the epidemiology, pathophysiology and diagnosis of androgenetic alopecia, an inherited hair loss condition that affects both men and women, and highlight the current and emerging treatment and management options.

Listeriosis is a food-borne bacterial infection that causes severe illness in at-risk populations. In this Primer, Disson et al. review the epidemiology and pathogenesis of the disease; discuss its diagnosis, prevention and management; and identify areas of research that need to be prioritized in the future.

Lupus nephritis is an autoimmune-mediated glomerulonephritis and a serious complication of systemic lupus erythematosus. In this Primer, Parodis and colleagues describe the epidemiology and pathophysiology of this disease, discuss current diagnosis and management, and highlight the effects on patient quality of life as well as future areas of research.

Peripheral artery disease is a vascular disorder characterized by narrowing of the peripheral arteries owing to atherosclerosis or thrombosis. In this Primer, Aboyans and colleagues review the epidemiology, pathophysiology, diagnosis and management of peripheral artery disease, and discuss areas for future research.