Acute respiratory distress in children is often a consequence of asthma. Other causes are subglottic laryngitis, epiglottitis, aspiration of a foreign body, acute bacterial pneumonia or pneumothorax. History and physical examination should differentiate between the various diseases. Asthma is characterized by recurrent symptoms and signs, while this is not the case with the other causes of acute breathlessness described. An asthma exacerbation is often preceded by one or more prodromes. In case of aspiration of a foreign body, like a peanut, immediate action is needed to prevent irreversible damage to the airways. Subglottic laryngitis and epiglottitis are both characterized by an inspiratory stridor; in case of epiglottitis immediate action is needed, while in case of subglottic laryngitis observation time is available in most cases. Pneumothorax as a cause of acute breathlessness is rare in childhood; it should be considered in male smoking leptosomic asthmatic adolescents.