New concepts in antimalarial use and mode of action in dermatology

Abstract

Although chloroquine, hydroxychloroquine and quinacrine were originally developed for the treatment of malaria, these medications have been used to treat skin disease for over 50 years. Recent clinical data have confirmed the usefulness of these medications for the treatment of lupus erythematosus. Current research has further enhanced our understanding of the pharmacologic mechanisms of action of these drugs involving inhibition of endosomal toll-like receptor (TLR) signaling limiting B cell and dendritic cell activation. With this understanding, the use of these medications in dermatology is broadening. This article highlights the different antimalarials used within dermatology through their pharmacologic properties and mechanism of action, as well as indicating their clinical uses. In addition, contraindications, adverse effects, and possible drug interactions of antimalarials are reviewed.

Figure 1

Structural formulas of the antimalarial drugs used in dermatology. Chloroquine and hydroxychloroquine are 4 amino‐quinolines. Quinacrine is an acridine dye.

Figure 2

The major proposed mechanism of action of antimalarial drugs: Interference with lysosomal acidification. Consequences of this lysosomotropic effect within macrophages, dendritic cells and lymphocytes are felt to underlay the therapeutic antiinflammatory effect of these drugs.