ALLERGY: CAUSES AND MANAGEMENT

An allergy is an immune system response to a foreign substance that’s not typically harmful to your body. These foreign substances are called allergens. They can include certain foods, pollen, or pet dander.

CAUSES

Why the immune system causes an allergic reaction when a normally harmless foreign substance enters the body is not clear. Researches is going on.

Allergies have a genetic component. This means parents can pass them down to their children. However, only a general susceptibility to allergic reaction is genetic. Specific allergies aren’t passed down. For example, if your mother is allergic to shellfish, it doesn’t necessarily mean that you’ll be, too.

Common types of allergens include:

• Animal products. These includepet dander, dust mite waste, and cockroaches.
• Penicillin and sulpha drugs are common triggers.
• Wheat, nuts, milk, shellfish, and egg allergies are common.
• Insect stings.These include bees, wasps, and mosquitoes.
• Airborne spores from mold can trigger a reaction.
• Pollens from grass, weeds, and trees, as well as resin from plants such as poison ivy and poison oak, are very common plant allergens.
• Other allergens.Latex, often found in latex gloves and condoms, and metals like nickel are also common allergens.

 Symptoms

Based on the substance, allergy symptoms might affect your skin, digestive system, sinuses, nasal passages, and airways. The severity of allergic responses can vary. In extremely severe instances, allergies can result in a potentially fatal reaction known as anaphylaxis.

Allergic rhinitis (Hay fever) can cause:

• Sneezing
• Itching of the nose, eyes, or roof of the mouth
• Runny, stuffy nose
• Watery, red, or swollen eyes (conjunctivitis)

A food allergy can cause:

• Tingling in the mouth
• Swelling of the lips, tongue, face, or throat
• Hives, also known as urticaria, is a kind of skin rashwith red, raised, itchy bumps.
• Anaphylaxis

An insect sting allergy can cause:

• A large area of swelling (edema) at the sting site
• Itching or hives all over the body
• Cough, chest tightness, wheezing or shortness of breath.
• Anaphylaxis

A drug allergy can cause:

• Hives
• Itchy skin
• Rash
• Facial swelling
• Wheezing
• Anaphylaxis

Atopic dermatitis, an allergic skin condition also called eczema, can cause skin to:

• Itch
• Redden
• Flake or peel

Anaphylaxis

• Some types of allergies, including allergies to foods and insect stings, can trigger a severe reaction known as anaphylaxis.
• Anaphylaxis is an acute multiorgan system reaction.
• A life-threatening medical emergency, anaphylaxis can cause you to go into shock.
• The most common organ systems involved include the skin, respiratory, cardiovascular, and gastrointestinal (GI) systems.
• Signs and symptoms of anaphylaxis include:
• Initially, patients often describe a sense of impending doom, accompanied by pruritus and flushing. This can evolve rapidly into the following symptoms.
• Cutaneous/ocular – Flushing, urticaria, angioedema, cutaneous and/or conjunctival pruritus, warmth, and swelling.
• Respiratory – Nasal congestion, rhinorrhoea, throat tightness, wheezing, shortness of breath, cough, hoarseness.
• Cardiovascular – Dizziness, weakness, syncope, chest pain, palpitations
• Gastrointestinal – Dysphagia, nausea, vomiting, diarrhoea, bloating, cramps.
• Neurologic – Headache, dizziness, blurred vision, and seizure (very rare and often associated with hypotension)
• Other – Metallic taste, feeling of impending doom.
• Symptoms usually begin within 5-30 minutes from the time the culprit antigen is injected but can occur within seconds. If the antigen is ingested, symptoms usually occur within minutes to 2 hours. In rare cases, symptoms can be delayed in onset for several hours.

DIAGNOSIS AND TREATMENT

If you experience symptoms of an allergic reaction, your  healthcare provider will perform an exam and ask you about your health history.

The doctor may want to order tests to determine what’s causing your allergy. The most commonly ordered types of allergy tests are:

• Skin tests
• Challenge (elimination-type) test
• Blood tests

Skin test

A skin test involves applying a small amount of a suspected allergen to the skin and watching for a reaction. The substance may be:

• taped to the skin (patch test)
• applied via a small prick to the skin (skin prick test)
• injected just under the skin (intradermal test)

A skin test is most valuable for diagnosing:

• Food allergies, such as allergies to shellfish or peanuts
• Mold, pollen, and animal dander allergies
• Penicillin allergies
• Allergies to venom, such as the kind secreted by bees or yellowjackets
• Allergic contact dermatitis, which is a rash you get after touching a substance.

Challenge (elimination-type) test

Challenge testing is useful in diagnosing food allergies. It involves removing a food from your diet for several weeks and carefully watching for symptoms when you eat the food again.

Blood test

A blood test allows the doctor to check your blood for antibodies against a possible allergen. An antibody is a protein your body produces to fight harmful substances.

Blood tests are an option when skin testing isn’t helpful or possible.

Treatment

Allergy treatments include:

• Allergen avoidance.Your provider will help you take steps to identify and avoid your allergy triggers. This is generally the most important step in preventing allergic reactions and reducing symptoms.
• Depending on your allergy, medications can help reduce your immune system reaction and ease symptoms. Your provider might suggest non-prescription or prescription medication in the form of pills or liquid, nasal sprays, or eyedrops.
• For severe allergies or allergies not completely relieved by other treatment, your provider might recommend allergen immunotherapy. This treatment involves a series of injections of purified allergen extracts, usually given over a period of a few years.

Another form of immunotherapy is a tablet that’s placed under the tongue (sublingual) until it dissolves. Sublingual drugs are used to treat some pollen allergies.

• Emergency epinephrine.If you have a severe allergy, you might need to carry an emergency epinephrine shot at all times. Given for severe allergic reactions, an epinephrine shot (Auvi-Q, EpiPen, others) can reduce symptoms until you get emergency treatment.

OUTLOOK

Allergies are common and don’t have life-threatening consequences for most people.

Proper allergy testing can help you pinpoint your exact triggers, which makes them easier to avoid.

Most allergies are manageable with avoidance, medications, and lifestyle changes. Working with your doctor or allergist can help reduce any major complications and make life more enjoyable.