MCAS

This condition involves inappropriate mast cell activation, resulting in excessive histamine release. Symptoms include flushing, gastrointestinal distress, and systemic effects like low blood pressure and anaphylaxis. MCAS can involve multiple organ systems.

Neuroinflammatory Disorders

Chronic Pain and Fibromyalgia

Histamine is linked to chronic pain through its role in inflammation and nerve sensitisation. When mast cells release histamine, it can irritate nearby nerves, increasing pain sensitivity. This process is common in conditions like fibromyalgia and migraines, where histamine contributes to widespread pain, headaches, and discomfort. Managing histamine levels may help reduce pain and improve symptoms.

Endometriosis

Both PCOS (polycystic ovary syndrome) and endometriosis may involve histamine through inflammation and hormone interactions, although the mechanisms differ.

1. PCOS: Histamine may worsen symptoms by promoting inflammation, which is often elevated in PCOS. Additionally, histamine's influence on insulin sensitivity and androgen levels could contribute to weight gain, irregular cycles, and other metabolic issues commonly seen in PCOS.

2. Endometriosis: Histamine plays a more direct role in endometriosis by driving inflammation around endometrial lesions and sensitising nerves, leading to chronic pain. Mast cells, which release histamine, are often overactive in endometriosis, potentially worsening pain and inflammation during menstrual cycles or when exposed to high-histamine foods.

Do you struggle with sleep?

Histamine plays a major role in regulating sleep and wakefulness. In the brain, histamine promotes alertness by activating specific regions, such as the hypothalamus. High histamine levels can make it harder to fall asleep, while low levels are linked to drowsiness. Disruptions in histamine signalling, such as from allergies, mast cell disorders, or medications, can lead to insomnia or poor-quality sleep.

Do you suffer from Cardiac Issues

Histamine can have significant effects on the cardiovascular system, particularly in conditions like systemic mast cell disorders. When histamine is released in large amounts, it can cause blood vessels to dilate, leading to low blood pressure (hypotension) and even fainting (syncope). It can also overstimulate the heart, resulting in a rapid heartbeat (tachycardia). These symptoms often occur during allergic reactions or mast cell activation episodes and can feel alarming, including dizziness, lightheadedness, or palpitations. Managing histamine levels with medications like antihistamines can help reduce these cardiovascular symptoms.

Do you suffer from Gastrointestinal (GI) Issues:

Histamine plays a key role in gut health and is linked to conditions like irritable bowel syndrome (IBS) and inflammatory bowel diseases. It affects how food moves through the digestive system (motility) and triggers immune responses in the gut. When histamine levels are too high, it can cause cramping, diarrhoea, bloating and inflammation, worsening these gastrointestinal issues.

Hypermobility

Histamine may play a role in hypermobility syndromes, such as hypermobile Ehlers-Danlos Syndrome (hEDS) or Hypermobility Spectrum Disorder (HSD), through its connection to mast cell activation and inflammation. Many people with hypermobility experience mast cell activation symptoms like flushing, hives, and gastrointestinal issues. Histamine release can also contribute to chronic pain, fatigue, brain fog and even cardiovascular symptoms like dizziness or fainting due to its effect on blood vessels. Mast cell stabilisers and low-histamine diets are sometimes used to help manage these overlapping symptoms.