Are these changes in your body caused by histamine? Let's find out for sure!

Do you suddenly feel itchy? Do you sneeze after sneezing? Or do you get a red rash on your body after a while after eating certain foods? These things have probably happened to you too. Most of the time, the person behind these discomforts is called histamine. Today, let's talk about what histamine is, why it is important for our bodies, and what happens when it increases.

What exactly is histamine?

Simply put, histamine is a chemical that occurs naturally in our bodies. It's like a little messenger that works in our bodies. It's stored inside certain cells in our bodies. It's mainly stored in two types of cells called mast cells and basophils . These cells are part of our immune system, the system that protects us from diseases. Think of it like a fortress. When an enemy (for example, a germ or pollen) comes from outside this fortress, the guards like these mast cells use a weapon called histamine to start the fight. Not only that, but this friend called histamine is also involved in helping our stomach digest food and in some brain functions.

Why does this histamine leave our body?

The main reason for the release of histamine from the body is allergic reactions . Let's see how it happens. 1. Allergy: Imagine that you have an allergy to dust. When you go to a place where there is dust, those dust particles (which we call allergens ) enter your nose. Then the mast cells in our body recognize these dust particles as an "enemy". They recognize them and start acting against them. At this time, the histamine inside the mast cells is suddenly released. Like a bomb going off. This histamine is what causes the sneezing, stuffy nose, and itchy eyes.

• Some common allergens are:
• Pollen
• Dust mites
• Animal dander
• Some foods (e.g. milk, eggs , peanuts , seafood )
• Insect stings
• Some medications

2. Injury or Infection: When the body is injured, the skin is broken, or a germ enters, histamine is released. Histamine helps to increase blood flow to the site of the injury, bringing in the necessary substances and germ-fighting cells to help heal the wound.

What does histamine do to the body?

When histamine is released from the body, it travels to different parts of our body and has various effects.

• Blood vessels : Histamine causes the tiny blood vessels in our body to widen. This is called vasodilation . This causes more blood to flow through them. This is why sometimes when you have an allergy, your skin turns red and you feel hot. Also, fluids start to leak out of the walls of the blood vessels. This causes swelling (Swelling/ Edema ), runny nose , and watery eyes.
• Respiratory system : Histamine causes the muscles in the lungs to constrict. This is called bronchoconstriction . This causes difficulty breathing and a feeling of tightness in the chest, especially in people with asthma .
• Skin: Histamine can stimulate nerve endings in the skin and cause itching/pruritus. It is also responsible for the appearance of red, swollen bumps (hives/urticaria) on the skin.
• Digestive system: Contraction of the muscles in the intestines can cause stomach cramps, nausea, vomiting, and diarrhea. Histamine also helps stimulate the secretion of stomach acid.
• Nervous system: Histamine also acts as a neurotransmitter in the brain. This means it helps carry messages between nerve cells. This is especially helpful in keeping us awake and alert. (That's why some older allergy medications make us sleepy, because they also reduce the activity of histamine in the brain.)

What are the symptoms of increased histamine?

The symptoms of histamine overload can vary from person to person, depending on how much histamine was released and which organ system was most affected.

• Skin symptoms:
• Skin redness, itching
• Eczema, rash
• Urticaria/Hives: Sudden, red, swollen, and intensely itchy patches of skin.
• Nose and throat symptoms:
• Sneezing
• Rhinorrhea or nasal congestion
• Itchy nose, throat, and palate
• Cough
• Swelling of the throat, change in voice
• Eye-related symptoms:
• Red, itchy eyes
• Tears flowing from the eyes
• Swelling of the eyelids
• Lung-related symptoms:
• Difficulty breathing, shortness of breath
• Feeling of tightness in the chest
• Wheezing (whistling) when breathing
• If you have asthma, an asthma exacerbation
• Digestive system related symptoms:
• Nausea, vomiting
• Stomach pain, bloating
• Diarrhea
• Other features:
• Headache (headache)
• Dizziness
• Low blood pressure (especially in severe cases)

Imagine that your friend Sugath ate some shrimp. Within half an hour, his whole body was itching and he had a red rash. He was having a hard time breathing. This could be because Sugath's body suddenly released a lot of histamine in response to the shrimp.

The most dangerous condition: Anaphylaxis

This is the most severe and life-threatening allergic reaction to histamine. This is called anaphylaxis . In this, a large amount of histamine is released throughout the body at once. This can occur within a few minutes. The main symptoms of anaphylaxis are:

• Severe difficulty breathing (occlusion of the airway due to swelling of the throat and tongue)
• Dizziness, feeling faint
• Heart palpitations
• Sudden drop in blood pressure
• Confusion
• Blue or pale skin

If you see any of these symptoms, it is a medical emergency. You should be taken to a hospital immediately. Delaying treatment can be life-threatening. The first treatment in such cases is an adrenaline (Adrenaline/Epinephrine) injection.

How to control the effects of histamine?

Fortunately, we have ways to control these discomforts caused by histamine. 1. Antihistamines: This is the main type of medication. These medications block the sites where histamine binds (called histamine receptors) . This prevents histamine from having its effect.

• First-generation antihistamines: These can cause some drowsiness (e.g., chlorpheniramine, diphenhydramine). Therefore, caution should be exercised when taking them at night or when performing tasks such as driving.
• Second-generation antihistamines: These are less sleepy (e.g., Loratadine, Cetirizine, Fexofenadine). They are best used during the day.

A doctor will decide which antihistamine is right for you and how long you need to take it. 2. Mast cell stabilizers:These medications work by blocking the release of histamine from mast cells. (Example: Cromolyn sodium). These come as nasal sprays and eye drops. 3. Corticosteroids: These are powerful medications that reduce inflammation. Sometimes, they are used short-term to control asthma in severe allergic conditions. 4. Avoiding triggers: If you know what you are allergic to, it is best to avoid those things as much as possible. For example, if you are allergic to dust, you can do things like keep your house clean and wear a mask when you go outside during pollen season.

What is Histamine Intolerance?

This is a little different than an allergy. Histamine intolerance is when our body is unable to properly break down histamine from food or from the amount of histamine produced within the body. The main reason for this is a decrease in the enzyme Diamine Oxidase (DAO) . In this case, the same symptoms as in an allergy (itching, headache, stomach problems) can occur. However, this occurs when eating foods high in histamine (e.g., aged cheese, fermented foods, wine, some vegetables and fruits). If you have any doubts about this, it is best to see a doctor and talk to them.

When should you see a doctor?

Usually, it's okay to buy an antihistamine from a pharmacy for minor allergic symptoms. However, in cases like these, you should definitely see a doctor:

• If you experience severe allergic symptoms frequently.
• If symptoms are not controlled by regular medications.
• If you feel difficulty breathing or chest tightness.
• If you experience any of the symptoms of anaphylaxis (this is an emergency!).
• If you want to find out exactly what you are allergic to (there are allergy tests for that).
• If there is a suspicion of histamine intolerance.

A doctor can accurately assess your condition and provide you with the best treatment and advice you need.

Finally, things to remember (Take-Home Message)

So, although histamine is an essential chemical for our bodies, it can sometimes be a bit troublesome.

• Histamine plays a key role in allergies, and also helps with wound healing and stomach function.
• Things like sneezing, itchy skin, hives, and nasal congestion can be caused by histamine.
• Anaphylaxis is the most dangerous condition caused by histamine. It is a medical emergency that requires emergency treatment.
• Antihistamines are the main medications that control the effects of histamine.
• If you have frequent or severe allergic symptoms, be sure to seek medical advice.

There is nothing to worry about. Most of these histamine-related conditions can be successfully managed. The most important thing is to pay attention to your body and seek proper medical advice when necessary. histamine, allergy, allergic reaction, antihistamine, anaphylaxis, urticaria, asthma, ஹிஸ்டின், அல்ஜி, அல்ஜி