Diamine oxidase (DAO), formerly called histaminase, is an enzyme that catabolizes various substrates including histamine and diamines. It is the degradative enzyme in the catabolic pathway of polyamines found in high activity in the mature upper villus cells of the rat intestinal mucosa (Luk et al., 1983; Wolvekamp and Debruin, 1994). Blood DAO activity has been well correlated with DAO activity in the villi of the small intestinal mucosa and also with the severity of small intestinal mucosal lesions.
When should I use
To investigate DAO deficiency.
Reduced DAO activity can lead to histamine overload and a pseudo-allergic reaction with symptoms such as dyspnoea, hypotension, reddening of the skin, sniffles, nettle rash with itching, nausea, stomach cramps, vomiting, diarrhoea and headaches.