What are allergies?

What are allergies?

Allergies occur when your immune system overreacts to a foreign substance (known as an allergen), that is normally harmless to most people.

Allergens can include: dust mites, pollen, food, drugs, and insect venoms.

Symptoms of an allergic reaction are very variable and can include:

Sneezing, itching, hives, shortness of breath, runny nose, coughing, and itchy eyes.

Hives

Severity of an allergic reaction

This can range from mild to life-threatening. A life-threatening reaction is known as anaphylaxis.

Symptoms that may require emergency care include:

• Swelling, redness, itching, or hives on the skin
• Itching or swelling of the lips or tongue
• Vomiting, diarrhea, or cramps
• Headache, nasal congestion, or watery eyes.

Symptoms of anaphylaxis

• Shortness of breath, wheezing, coughing, chest pain, or tightness
• Weak pulse, dizziness, or faintness
• Confusion or feeling of impending doom
• Loss of consciousness

The severity of the reaction may increase with repeated exposure.

Different types of allergy

Everyone’s allergies are different. But they can be loosely divided into these 4 groups.

1. Food allergies

Food allergies can trigger swelling, hives, nausea and fatigue. It may take a while for a person to realise that they have a food allergy. If you have a serious reaction after a meal and you’re not sure why, see your GP soon. They may be able to find the cause of your reaction or refer you to a hospital consultant.

2. Seasonal allergies

Hay fever symptoms can mimic those of a cold. They include a blocked and runny nose, and swollen runny eyes. You can manage these symptoms at home using over-the-counter treatments. See your doctor only if your symptoms become unmanageable.

3. Skin allergies

A skin problem may be a sign of an allergy elsewhere. Or may be the direct result of exposure to an allergen – i.e. your skin is allergic to something its exposed to (contact dermatitis).

For example, eating a food you’re allergic to can cause several symptoms. You may experience tingling in your mouth and throat. You may also develop a skin rash.

Contact dermatitis, however, is the result of your skin coming into direct contact with an allergen. This could happen if you touch something you’re allergic to, such as a cleaning product or plant.

Types of skin allergies include:

• Rashes. Areas of skin are irritated, red, or swollen, and can be painful or itchy
• Eczema. Patches of skin become inflamed and can itch and bleed

Contact dermatitis. Red, itchy patches of skin develop almost immediately after contact with an allergen

• Urticaria (hives). Red, itchy, and raised welts of various sizes and shapes develop on the surface of the skin
• Swollen eyes. Eyes may be watery, itchy or puffy
• Itching. There’s irritation or inflammation in the skin
• Burning. Skin inflammation leads to discomfort and stinging sensations on the skin.

4. Severe allergies

Severe allergies can cause anaphylaxis. This is a life-threatening emergency that can lead to breathing difficulties, light-headedness, loss of consciousness, and even cardiac arrest. If you’re experiencing these symptoms after coming in contact with a possible allergen, seek medical help immediately.

Summary

We have described what are allergies. We hope it has been helpful.