Allergy

What is allergy?

An allergy is a hypersensitivity disorder of the immune system. Symptoms include red eyes, itchiness, and runny nose, eczema, hives or an asthma attack. Allergies can play a major role in conditions such as asthma. In some people, severe allergies to environmental or dietary allergens or to medication may result in life-threatening reactions called anaphylaxis. Food allergies and reactions to the venom of stinging insects such as wasps and bees are more often associated with these severe reactions.

Allergic reactions occur when a person’s immune system reacts to normally harmless substances in the environment. An allergen is a substance that causes a reaction. These reactions are acquired, predictable, and rapid. Allergy is one of four forms of hypersensitivity.This reaction results in an inflammatory response which can range from uncomfortable to dangerous.

What are the signs and symptoms of allergy?

In allergy we can see following signs and symptoms –

• Nose – Swelling of the nasal mucosa, runny nose, sneezing.

• Eyes – Redness and itching.

• Airways – Sneezing, coughing, wheezing and dyspnea, sometimes outright attacks of asthma, in severe cases the airway constricts.

• Ears – Feeling of fullness, possibly pain, and impaired hearing.

• Skin – Rashes, hives (urticaria).

• Gastrointestinal Tract – Abdominal pain, bloating, vomiting, diarrhea.

How to diagnose allergy?

We can do following test to diagnose allergy –

Blood testing

An allergy blood test is quick and simple. Unlike skin-prick testing, a blood test can be performed irrespective of age, skin condition, medication, symptom, disease activity, and pregnancy. Adults and children of any age can take an allergy blood test. For babies and very young children, a single needle stick for allergy blood testing is often more gentle than several skin tests.

We can detect multiple allergens with a single blood sample. Allergy blood tests are very safe, since the person is not exposed to any allergens during the testing procedure.

Skin prick allergy testing

Skin testing is also known as “puncture testing” and “prick testing” due to the series of tiny punctures or pricks made into the patient’s skin. Small amounts of suspected allergens and/or their extracts (e.g., pollen, grass, mite proteins, peanut extract) are introduced to sites on the skin marked with pen or dye. We use small plastic or metal device to puncture or prick the skin. Sometimes, doctor inject the allergens “intradermally” into the patient’s skin, with a needle and syringe. Common areas for testing include the inside forearm and the back.

If the patient is allergic to the substance, then a visible inflammatory reaction will usually occur within 30 minutes. This response will range from slight reddening of the skin to a full-blown hive (called “wheal and flare”) in more sensitive patients similar to a mosquito bite.

Patch allergy testing

Patch testing is a method used to determine if a specific substance causes allergic inflammation of the skin. It tests for delayed reactions. Adhesive patches, usually treated with a number of common allergic chemicals or skin sensitizers, are applied to the back. Doctor examine the skin for possible local reactions at least twice, usually at 48 hours after application of the patch, and again two or three days later.

What is the treatment of allergy?

Treatments for allergies include avoiding known allergens, steroids that modify the immune system in general, and medications such as antihistamines and decongestants which reduce symptoms. Immunotherapy uses injected allergens to desensitize the body’s response.

Antihistamines, glucocorticoids, epinephrine (adrenaline), theophylline and cromolyn sodium. Anti-leukotrienes, such as montelukast or zafirlukast. Anti-cholinergics, decongestants, mast cell stabilizers.