Nonsteroidal anti-inflammatory drugs (NSAIDs) are the drugs most commonly involved in hypersensitivity drug reactions. Such reactions can be due to the release of inflammatory mediators in the absence of specific immunologic recognition, or immunoglobulin E (IgE)- or T-cell–selective responses.

The former include upper and lower airway symptoms in patients with chronic underlying respiratory disease, the exacerbation of chronic spontaneous urticaria, and the induction of cutaneous symptoms.

The latter include selective responses to a single NSAID with good tolerance to strong cyclooxygenase-1 inhibitors, with a putative IgE or T-cell mechanism proposed. These reactions can be acute or delayed.