Histamine and Rosacea

What’s the relation between rosacea and histamine?

Rosacea is a chronic skin condition that causes redness and visible blood vessels in your face. It may also produce small, red, pus-filled bumps. The cause of rosacea is unknown, but it could be due to some combination of hereditary and environmental factors.

Histamine is a compound that is released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries. It plays a central role in many allergic reactions.

The relationship between rosacea and histamine is not completely understood, but it’s believed that histamine might play a role in the inflammation and redness associated with rosacea. Histamine can cause blood vessels to dilate, which can lead to flushing and redness, symptoms commonly seen in rosacea. Additionally, some people with rosacea have reported that their symptoms worsen when they consume foods high in histamine.

What is histamine?

Histamine is a compound that is involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. It is involved in the inflammatory response and has a central role as a mediator of itching.

Histamine is produced by basophils and by mast cells found in nearby connective tissues. It’s stored in the granules of these cells and is released as part of an immune response. When an allergen triggers the immune system, these cells release histamine into the surrounding tissues.

Histamine increases the permeability of the capillaries to white blood cells and some proteins, allowing them to engage pathogens in the infected tissues. It can cause constriction of smooth muscle, especially in the lungs, and dilation of blood vessels, which can lead to a drop in blood pressure. It also increases secretion of gastric acid in the stomach.

In allergic reactions, such as hay fever, histamine is released in large amounts and can cause symptoms like itching, redness, swelling, and runny nose. Antihistamines are drugs that block the action of histamine and can provide relief from these symptoms.

Histamine is a biogenic amine, a type of molecule derived from an amino acid. In the case of histamine, it’s derived from the amino acid histidine. Histamine is synthesized in the body and stored primarily in mast cells and basophils.

When the body encounters a potential threat, such as an allergen or pathogen, mast cells and basophils release histamine as part of the body’s immune response. This release is part of the body’s inflammatory response, and it’s what causes many of the symptoms we associate with inflammation, such as redness, swelling, and itching.

Histamine achieves these effects by binding to histamine receptors, which are found on a variety of cells throughout the body. There are four known types of histamine receptors: H1, H2, H3, and H4. Each type of receptor has different functions and is found in different types of cells.

H1 receptors are found in smooth muscle, endothelial cells, and central nervous system tissue. They’re responsible for contraction of smooth muscle and dilation of capillaries, among other effects.

H2 receptors are found in the gastric mucosa, where they stimulate the secretion of gastric acid. They’re also found in the heart, where they can stimulate heart rate and contraction.

H3 receptors are found in the central nervous system and to a lesser extent in the peripheral nervous system, where they act as autoreceptors and heteroreceptors on histaminergic and non-histaminergic neurons, respectively.

H4 receptors are found primarily in bone marrow and white blood cells, and they’re involved in the chemotaxis and cellular activation of a subset of immune cells.

Histamine plays a crucial role in the body’s immune response, but it can also contribute to allergic reactions when the immune system overreacts to harmless substances like pollen or pet dander. Antihistamine medications work by blocking the action of histamine, thereby reducing the symptoms of the allergic reaction.

What does histamine do in the body?

Histamine plays several roles in the body, primarily related to the immune system, digestion, and the nervous system. Here are some of its key functions:

Immune Response:

Histamine is released by immune cells in response to an injury or an allergic reaction. It helps your body fight off potential threats by increasing blood flow to the area, causing inflammation. This allows more white blood cells to reach the area and fight off any pathogens. The inflammation can cause symptoms such as redness, swelling, and itching.


Histamine stimulates the production of stomach acid, which helps break down food in the stomach. This is why some people who take certain types of antihistamines may experience digestive issues, as these medications can interfere with the action of histamine in the stomach.

Nervous System Function:

Histamine acts as a neurotransmitter, a chemical messenger that transmits signals in the brain. It plays a role in regulating the sleep-wake cycle, appetite, learning, and memory.


Histamine causes the blood vessels to expand (vasodilation), which allows for increased blood flow. This is why areas of inflammation become red and warm to the touch.


In the lungs, histamine can cause the airways to constrict, making it harder to breathe. This is part of the body’s defense mechanism to prevent foreign substances from entering the lungs. However, in conditions like asthma, this response can be harmful.


Histamine is a major factor in causing itching, especially in allergic reactions. When histamine is released in the skin, it causes an itching sensation.

It’s important to note that while histamine is essential for many bodily functions, too much histamine can cause problems. This is seen in allergic reactions, where an overproduction of histamine can lead to symptoms like itching, swelling, redness, and in severe cases, anaphylaxis. Certain medications, known as antihistamines, are used to block the effects of histamine and can help alleviate these symptoms.

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