A severe form of exacerbation of asthma, AAA is defined by the presence of a least one sign of clinical severity during the attack. AAA is often preceded by prodromal symptoms that should indicate the need to increase maintenance treatment and eliminate possible triggering factors. Initial treatment of AAA should be made as early as possible and should associate high-dose oxygen, nebulisations of beta-2-agonists and corticosteroid infusion. The immediate prognosis of AAA is particularly related to the initial response to appropriate treatment. When objective improvement criteria are met, discharge can be considered, with short-term outpatient corticosteroid treatment. In more severe stages, beta-2 agonists and anti-cholinergic agent nebulisations are useful. The interest of using other bronchodilators (adrenalin, theophylline) is debated. In case of very severe asthma attack, inhalation of a mixture of helium and oxygen can avoid the need for intubation and mechanical ventilation. Subsequent to AAA, rehabilitation and pulmonary follow-up are indicated in order to prevent recurrence.