The role of the complement system in dermatological disease

Complement bridges the innate and adaptive immune systems, recognizing and eliminating microorganisms and maintaining tissue homeostasis. Perturbations in the complement cascade can be of profound clinical consequence, with dermatological associations including impaired control of infectious agents, predisposition to autoimmune disease (notably systemic lupus erythematosus) and hereditary and acquired angioedema. In this review, the authors describe the fundamentals of the complement cascade and discuss the clinical manifestations of defects in signaling in order to contextualize the rational testing of complement components and functional assays in dermatological practice.