Rationale: Case reports describe suppression of the hypothalamic-pituitary-adrenal (HPA) axis caused by local corticosteroids, most often with inhalation corticosteroids. The exact prevalence is not known. Early recognition is important, because suppression of the HPA-axis can lead to significant morbidity and mortality. Suppression of the HPA axis might occur more often when a Cytochrome P450 3A4 (CYP3A4) inhibitor, e.g. ritonavir, is used next to the local corticosteroid, a combination often used by human immunodeficiency virus (HIV)-patients. Cortisol can be determined in hair. This non-invasive analysis could help in diagnosis of suppressed HPA-axis.