People who have Histamine Intolerance can experience a diverse range of different symptoms. A diagnosis requires at least 2 typical symptoms of HIT.

For more information about what to discuss with your doctor & what to consider before you start a low-histamine diet have a look at the first steps page.

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

  • 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)
  • Flushing of face and/or chest

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
  • You should check with the help of your GP (doctor or physician) for other intolerances of some specific foods or food groups, and allergies.
  • Your GP should automatically also check for any other underlying health issues.
  • Do not change any medication you have been given unless you have talked to your GP, and try to find alternatives with them if necessary.
  • Going on a diet and assuming you have HIT is not a useful way of tackling the problem.