[Acetylsalicylic acid: hypersensitivity, intolerance, or allergy?]

After a century of therapeutic use of acetyl salicylic acid (ASA), the different mechanisms involved leading to the therapeutic activity and to the various clinical reactions (even life threatening) observed in patients sensitive to ASA or in general to the non steroidal anti-inflammatory drugs (NSAID's) are still to be discovered or confirmed. During the last century a lot of scientific results have been published in favour of a wide panel of mechanism including an humoral (IgE and/or IgG) or a cellular (lymphocytes) immune reaction, inhibition of the cyclooxygenases, a cellular activation (mast cells, basophils, eosinophils and platelets), a competition at the serum albumin level and an activation of the complement cascade. In general the same actors than in the anaphylactic reaction are found (mediators, cellular activation and amplification systems). It is clear today that these reactions for which an accurate diagnosis is mandatory cannot be explained by a single mechanism, which is the case of a lot of other allergens.