[Asthma and aspirin]

Aspirin (ASA) is an important cause of asthma so that ASA induced asthma (AIA) is considered a disease. Its prevalence is of 0.3-0.6 in the general population but it raises to 21% in the asthmatic one. Middle aged female are the most affected. AIA generally begins with a non allergic rhinitis, complicated sometimes with polyps, that evolves secondarily in asthma. The disease is often so severe to need oral corticosteroids to be controlled. It persists independently to the intake of ASA. From a pathogenetic point of view the interaction of ASA with the arachidonic acid metabolism seems to be important. The inhibition of cyclo-oxygenase (COX) induces an activation of lypo-oxygenase with an increased synthesis of leukotrienes. In ASA intolerant patients there is also an activation of LTC4 synthetase, enzyme responsible for the synthesis of leukotrienes. Clinical history is very important to diagnose the disease but to confirm the diagnosis sometimes the provocation test is mandatory. Oral and bronchial challenges can be dangerous, while nasal challenge is safer even if must be better standardized. Patients must not use antiinflammatory drugs with the same mechanism of action of ASA; COX-2 inhibitors are generally well tolerated. Antileukotrienes are useful to treat asthma, in association with steroids. Desensitization can be used in very selected patients.