Paronychia is inflammation of the nail folds and may be either acute or chronic. Acute paronychia occurs rapidly and is associated with redness, pain, and, in the case of infection, purulent drainage. Chronic paronychia lasts for more than 6 weeks and is associated with erythema, loss of the cuticle, and often nail dystrophy.

Acute paronychia is generally due to infectious etiologies, while chronic paronychia is typically due to irritants. Medications are also responsible for some acute and chronic paronychias and correlate with the introduction of the drug. Reported drug culprits include retinoids, lamivudine, cyclosporine, indinavir, azidothymidine (AZT), cephalexin, sulfonamides, cetuximab, gefitinib, fluorouracil (5FU), methotrexate, vandetanib, capecitabine, doxorubicin, and docetaxel. The paronychia typically resolves once the medication is discontinued.