The ingestion of histamine-rich food or of alcohol or drugs that release histamine or block DAO may provoke diarrhoea, headache, rhinoconjunctival symptoms, asthma, hypotension, arrhythmia, urticaria, pruritus, flushing, and other conditions in patients with histamine intolerance.[v]

Symptoms involved can be two or more of the following:

Digestive tract

  • Diarrhoea
  • Diarrhoea alternating with normal motions (Irritable Bowel Syndrome – IBS)
  • Chronic constipation
  • Flatulence and feeling of fullness
  • Stomach cramps
  • Stomach ache
  • Nausea
  • Vomiting

Symptoms affecting head and face

  • Flushing of face and/or chest (very common symptom)
  • Headaches, similar to migraine
  • Runny nose and weepy eyes, although there is no clinical sign of allergies
  • Fits of dizziness
  • Extreme tiredness, feeling knocked out
  • Quinke Oedema (swellings mostly appearing around eyes and lips, sometimes in the area of the throat)

Skin problems

  • Skin rashes, itchiness
  • Eczema,
  • Urticaria
  • Acne (pimples)

Chest area

  • Asthma
  • Cardiac arrhythmia, such as a fast beating or irregular heart beat


  • Dysmenorrhoea (severe period pains)
  • HIT symptoms go away during pregnancy and return after birth of child

Other symptoms

  • Chills and shivers
  • Low blood pressure
  • Circulatory collapse
  • Sudden psychological changes (e.g. aggressiveness, inattentiveness, lack of concentration)
  • Sleep disorder[vi]

A summary of histamine-mediated symptoms and their interlinked connection with histamine receptors (H1, H2, H3, H4) which determines the application of appropriate antihistamine medication for the patient can be found here:

Histamine and histamine intolerance
Laura Maintz, Natalija Novak (2007)
The American Journal of Clinical Nutrition 85 (5) p. 1186, FIGURE 1



HIT symptoms can be triggered by one or a combination of several causes:

  • Medication that suppresses the enzyme Diamine oxidase or N-Methyltransferase.


Sources include:

[v] Histamine and histamine intolerance. Laura Maintz, Natalija Novak (2007), The American Journal of Clinical Nutrition 85 (5) p. 1185-96

[vi] Food-induced histaminosis as an epidemiological problem: Plasma histamine elevation and haemodynamic alterations after oral histamine administration and blockade of diamine oxidase (DAO); J. Sattler, D. Häfner, H. -J. Klotter, W. Lorenz, P. K. Wagner (1988); Agents and Actions 23 (3-4) p. 361-365

Jarisch, R. “Histamin-Intoleranz, Histamin und Seekrankheit”, Thieme Verlag, 2nd Edition