How are Cortisol and allergy related?

Cortisol, the primary human stress hormone, has complex interactions with the immune system. It acts via the glucocorticoid receptor on immune cells and can both suppress inflammation and, under chronic stress, modulate immune responses. In allergies, the immune system overreacts to harmless environmental substances (allergens). Theoretically, elevated cortisol can dampen allergic inflammation, e.g., in hay fever or asthma. Conversely, chronic stress with sustained cortisol elevation may promote allergic sensitization by shifting the TH1/TH2 balance. However, the provided context contains no direct studies linking cortisol and allergy. The evidence is therefore mixed: plausible mechanisms exist, but robust human trials are lacking to support clinical recommendations. A single cortisol test (blood, saliva) is not valid for diagnosing or managing allergies. For allergy symptoms, consultation with an allergist is essential.