Cutaneous adverse drug reactions (CADRs) are a group of clinical manifestations affecting the skin, mucous membranes, and skin appendages secondary to drug exposure. Cutaneous involvement occurs in up to 45% of adverse drug reactions, of which 10% corresponds to hospitalized patients.

The most common are maculopapular rash, urticaria/angioedema, fixed drug eruption, lichenoid eruptions, and erythema multiforme. Less common but potentially life-threatening dermatoses include erythroderma, serum sickness disease, acute generalized exanthematous pustulosis (AGEP) and symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN).

Any drug can induce a drug-induced skin reaction; the most frequent culprits are antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), antiepileptics.

Drug-induced skin reactions are classified as type A (exacerbation), type B (unpredictable), and by phenotype. Risk factors include age, as it affects children and the elderly more frequently; female sex; polypharmacy; hospitalization; previous drug eruption; and kidney and liver disease, among others.

The common pathogenesis of severe drug eruptions includes a genetic link with HLA and non-HLA genes, drug-specific T-cell- mediated cytotoxicity, T-cell receptor restriction, and other cytotoxicity mechanisms.

Diagnosis of a drug eruption involves a thorough interview and the timeline of the dermatosis's onset a detailed clinical, morphological, and topographic examination; and staging studies such as laboratory tests and/or skin biopsy.

The treatment should include discontinuation of the suspected medication, and depending on the severity; Immunoglobulin G, topical or systemic corticosteroids, and cyclosporine A.