Can taking anti-histamines lead to histamine intolerance?

Allergy symptoms are caused by the release of histamine – so it seems logical to reach for an antihistamine to solve your problems. But, while antihistamines may reduce your symptoms in the short term, they do not address the underlying problem, can stop working over time and may even contribute to histamine intolerance!

What is histamine?

Allergy symptoms come about when your body reacts to foods and environmental substances that are usually harmless, triggering the release of histamine.

Histamine then interacts with one of four types of proteins (also known as histamine receptors), which regulate different bodily functions and can spark different symptoms:

  • H1 – causes sleep disturbance, itching, airway constriction, and contraction of the small intestine and eyes
  • H2 – stimulates gastric acid production, muscle relaxation, widens blood vessels and blocks antibody synthesis
  • H3 – decreases the release of neurotransmitters in the central nervous system, which can affect things like memory, sleep, energy and appetite
  • H4 – generates inflammation in the body

Why do antihistamines work?

Antihistamines do not remove histamine from your body. Rather, they block the effects of histamine on your H1 and H2 receptors, which reduces common allergy symptoms like itching, sneezing, watery eyes and hives.

Can anti-histamines stop working over time?

Antihistamines may stop working when used long term. But, for some, this can happen after only 7-20 days of continuous use (1).

The result? The body needs a higher dose of antihistamines to block new receptors and symptoms are more intense when you aren't taking antihistamines.

Can antihistamines contribute to histamine intolerance?


While antihistamines block your H1 and H2 receptors, they do not block histamine from interacting with your H3 and H4 receptors. So, when H1 and H2 receptors stop soaking up all that histamine, it can mean that there's an excess of histamine floating around your body. It also means that your H3 and H4 receptors receive all the histamine, which can create an imbalance and may contribute to the development of histamine intolerance.

Do you struggle with allergy-related symptoms?

At HWA, we perform a natural allergy treatment called Positive Association Technique (PAT), which may help reduce your reactions and help manage the symptoms.

PAT is a non-invasive holistic therapy, which:

  • draws on acupressure and kinesiology techniques
  • aims to re-train your body
  • may reduce your reactions to food and environmental substances that may be causing or exacerbating your symptoms

This blog is intended as general information only. PAT cannot diagnose or cure allergies – it is intended to decrease reactions and help manage symptoms. It is not intended to raise unrealistic expectations. If symptoms persist, consult your GP.


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