Circadian rhythms in the cutaneous reactivity to histamine and selected antigens, including phase relationship to urinary cortisol excretion.

Data show that intradermal skin reactions to histamine, house dust and grass pollen extracts follow a prominent circadian pattern, the response elevated in the afternoon, peaking in the evening and with a morning trough. Urinary hydrocortisone excretion curves exhibit agreement in antiphase timing.