Let's learn about histamine in simple terms? How allergies develop and more information!

Do you often itch? Do you sneeze? Or do you feel strange when you eat certain foods? Histamine is often involved in these things. Today, let's talk about what histamine is, why it is important for our bodies, and how it can sometimes cause us problems.

What is histamine? Simply put...

Simply put, histamine is a chemical produced by our immune system that carries messages between cells. It acts like a postman. Histamine has many jobs in our bodies, but we know it best for its association with allergies and a condition called anaphylaxis, which can sometimes be life-threatening.

Now, look, an allergy is when our immune system overreacts to a protein (we call these allergens) that is normally harmless to our body. Imagine that you are allergic to dust. Then, even though dust is not a problem for a normal person, your body sees it as an enemy.

This is when a chain of reactions occurs, and histamine is finally released. This is when the symptoms of an allergy (itchy skin, runny nose, red eyes) appear. Most of the time, these symptoms are limited to one area of ​​the body. But sometimes, if this immune response becomes severe, a condition called anaphylaxis can occur, affecting the entire body. This is very dangerous and can even be life-threatening.

Where is histamine found in our body?

Histamine in our bodies is mainly stored in a type of cell called mast cells and another type of white blood cell called basophils .

Mast cells are a type of white blood cell found in connective tissue (that is, the tissue that holds the body together) throughout our bodies. They can be found in particular:

• Under our skin.
• Blood vessels and lymph vessels are close together.
• In the nerves.
• These are also present in the lungs and intestines.

Basophils are another type of white blood cell . They are most abundant in the blood.

What does histamine do to our body?

Histamine controls many processes in our body. It plays a key role, especially when there is an inflammatory response in the body. The effect of a histamine depends on the histamine receptor it binds to. It's like each door has its own key. Scientists have so far identified four types of histamine receptors. Let's take a look at what each type does.

What happens to H1 receptors?

These H1 receptors are found throughout our bodies. They are particularly found in brain cells (neurons), smooth muscle cells in the airways, and blood vessels.

It is when the H1 receptors are activated that the symptoms of allergy and anaphylaxis that we discussed earlier appear. That is:

• Itchy skin (pruritus).
• Widening of blood vessels (vasodilation).
• Low blood pressure (hypotension).
• Increased heart rate (tachycardia).
• Flushing.
• Narrowing of the airways (bronchoconstriction) - This can cause difficulty breathing.
• Pain.
• Fluid leakage through the walls of blood vessels (vascular permeability) - This is what causes swelling.

Some of these changes are what cause things like sneezing, nasal congestion, and runny nose (rhinorrhea) .

In addition to allergic reactions, H1 receptors help with other things. These include:

• Control our sleep and wake cycles.
• Control your eating habits.
• Control body temperature.
• These also affect our emotions.
• These H1 receptors are also important for memory and learning.

What happens to H2 receptors?

H2 receptors are mainly found in the acid-producing cells of our stomach, in smooth muscle cells, and in heart cells.

When H2 receptors are activated, the following things can happen:

• Secretion of stomach acid. This helps in digestion .
• Stimulation of mucous glands in the respiratory tract.
• Fluid leakage from blood vessels (vascular permeability).
• Low blood pressure (hypotension).
• Flushing.
• Headache.
• Increased heart rate (tachycardia).
• Narrowing of the airways (bronchoconstriction).

Imagine, if you have a condition like heartburn or gastritis, sometimes doctors will prescribe H2 receptor blockers to reduce the production of acid in the stomach.

What are H3 receptors?

H3 receptors are mainly involved in the functioning of the blood-brain barrier . They are found on neurons in our central nervous system . H3 receptors control the release of histamine, as well as the release of other important neurotransmitters such as dopamine, norepinephrine, and acetylcholine .

Scientists are currently researching drugs that act against H3 receptors (antagonists) to see if they can be used as a treatment for neurodegenerative diseases .

What happens to H4 receptors?

H4 receptors are found in our bone marrow and on hematopoietic cells . These hematopoietic cells are the basic, immature cells that have the ability to make all the types of blood cells in our body. So H4 receptors play an important role in the formation of some types of blood cells.

Additionally, these H4 receptors are also linked to inflammatory disorders and autoimmune diseases (i.e., diseases in which our body's immune system attacks our own cells).

What are the conditions associated with histamine?

Histamine plays a key role in a number of allergy-related diseases. Here are a few examples:

• Skin diseases like atopic dermatitis (eczema).
• Contact dermatitis: This can occur when certain things come into contact with the skin. For example, plants like poison ivy, perfumes, metals like nickel, and preservatives.
• Allergic rhinitis (hay fever): This can be caused by things like pollen, pet dander, dust mites, mold, and cockroaches.
• Allergic asthma: This is also caused by the same allergens that cause hay fever.
• Allergic conjunctivitis: This is when the membrane over the white part of the eye (conjunctiva) becomes swollen and inflamed due to allergens.

What is Histamine Intolerance?

This is a little different. Histamine intolerance is a condition that occurs when your body has too many histamines. This can happen when your body can't break down histamine properly. This can cause a variety of symptoms:

• Headaches or migraines.
• Nasal congestion.
• Tired.
• Hives.
• Digestive problems.
• Irregular menstrual cycles in women.

How do I reduce histamine in the body? Is there any medicine?

Yes, there are medications that can help control histamine levels. Doctors recommend these.

• H1 antihistamines: These are the ones we usually use for allergies (e.g., pollen, animal dander). These medications block the H1 receptors. They can be purchased with a prescription from a doctor or over-the-counter (OTC). They come in various forms, including pills, lotions, creams, and eye drops.
• H2 antihistamines: These help with stomach conditions, such as peptic ulcer disease , gastroesophageal reflux disease (GERD ), and indigestion (dyspepsia) . They block H2 receptors and reduce stomach acid production.
• Corticosteroids: These medications, called steroids, help with inflammatory conditions and allergies caused by histamine. For example, many inhalers for asthma contain steroids.
• Epinephrine injections: These are used for severe allergic reactions (anaphylaxis) or asthma emergencies. Epinephrine opens the airways and increases blood pressure.
• Some supplements: Research has shown that supplements like Vitamin C, Copper, and Vitamin B6 can help reduce histamine levels. But remember, you should always talk to your doctor before starting any supplement.

When should you see a doctor for histamine problems?

If you have started to experience seasonal allergies and they are affecting your daily activities, you should definitely see a doctor. He or she can do allergy testing to determine what you are allergic to and then recommend appropriate treatment. Also, if you feel like you have symptoms of the aforementioned histamine intolerance , it is a good idea to see a doctor.

Although histamine is a substance that helps our body perform normal functions like sleep and memory, it can sometimes cause problems if our bodies overreact to things that are not harmful. So if things like allergies are affecting your life, it is wise to seek medical advice.

Take-Home Message

• Histamine is an important chemical produced by our immune system that carries messages between cells.
• Allergies occur when our body overreacts to a normally harmless substance (allergen) and releases histamine.
• Histamine has four types of receptors: H1, H2, H3, and H4, and each receptor has different effects on the body.
• Histamine is directly linked to conditions like allergies, eczema, hay fever, and asthma.
• Histamine intolerance is a condition caused by an increase in histamine in the body.
• Histamine can be controlled with medications such as antihistamines and corticosteroids.
• If you have allergy symptoms or a histamine problem, definitely see a doctor for advice. Don't just go do whatever you feel like doing.

So, I hope you now have a better understanding of histamine. Stay healthy!

` Histamine, Allergies, Immune System, H1 Receptor, H2 Receptor, Antihistamine, Anaphylaxis, Mast Cells