| Allergic reaction can be triggered by every day substances such as talcum powder, mosquito repellent or hair from pets
Life is miserable if you spent a lot of time sneezing, wheezing and itching. Allergies can affect efficient functioning. A drippy nose and an itchy skin make concentration difficult. To top it all, allergies serve no useful purpose. They are the result of the body’s misguided idiosyncratic attack on allergens, which are usually common, every day substances. Allergies are generally harmless and irritating, though unfortunately a sufficiently severe reaction can be fatal.
Allergens can be inhaled, eaten or come into contact with the skin. They may be minuscule particles of pollen, dust, chemicals, tobacco or wood smoke, cockroach dander, mites from animals, hair from cats or dogs, mosquito repellents or talcum powder. The same response can be precipitated by changes in temperature or exercise.
When an allergen enters the body, it comes into contact with B lymphocytes, a type of white blood cell. These cells produce immunoglobulin (usually IgE) which attaches itself to the allergen. This produces a cascading reaction during which several chemicals, including histamine, are released. These produce the characteristic symptoms of allergy.
Nasal allergies cause blocked, itchy, runny noses and red, watery eyes. This may be followed by violent sneezing. Attacks subside on their own in 15-20 minutes only to return several times a day. Treatment involves using nasal decongestants three to four times a day for no longer than three or four days. After this time, the response may decrease and there may be rebound congestion. Saline nose drops are safer. For long standing allergies, steroid or chromolyn nasal sprays can be used as prescribed. Non-sedating anti-histamines like fexofenadine and loratadine help to dry the nasal secretions.
Allergies may not stop in the nose and may progress to a dry, irritating, wheezy cough. This episodic allergic asthma is caused by the release of histamine-like chemicals from the lining of the lung passages. They cause the airways to tighten and narrow. The air supply is compromised further by the copious secretion of mucous.
Asthma is treatable. Medication can be delivered directly and efficiently to the lungs with inhalers, rotahalors and home nebulisers. Relief is immediate. Inhaled medication goes directly to the site where it is needed. Usually, a broncho dilator provides initial rapid relief and a corticosteroid or chromolyn reduces inflammation.
Syrups and tablets on the other hand go to the stomach, get absorbed, enter the blood stream and then reach the lungs. They take longer to act and do not afford immediate relief. There is a greater chance of developing side effects.
Patients can use peak flow meters and measure their own rate of exhalation. The value drops even before wheezing is obvious. Patients can start treatment early and control their symptoms better. Physical exercise and yoga help to correct faulty breathing techniques, increase vital capacity and improve general health. Skin allergy occurs as a result of contact with insects, plants, dyes, chemicals, cosmetics, latex or as a response to ingested food, preservatives, colouring substances or medication. Metals used in costume jewellery or kumkum can cause “contact dermatitis”. It causes itchy red rashes, blisters or swelling. They reappear every time the person comes into contact with the offending allergen. Symptoms set in within two days and may take up to two weeks to subside.
To relieve itching and rash —
* Apply a paste of water and baking soda or calamine lotion on the area
* Steroid creams may be prescribed for local application. But they should not be applied on cracked or blistered skin
* Anti-histamines may have to be taken for a few days
The best way to prevent allergy is to avoid contact with the allergen if it can be identified.
General prevention —
* Keep the air in the house clean by using a vacuum cleaner instead of a broom. Get rid of cockroaches
* Avoid cotton mattresses and change bed linen regularly
* Avoid mosquito repellents, agarbattis and firecrackers
* Do not smoke and also avoid second-hand cigarette smoke
Gastro esophageal reflux disease (Gerd) aggravates nocturnal wheezing. Treatment for Gerd reduces attacks. Also, avoid aspirin and non-steroidal anti-inflammatory agents.
Allergies run in families with many members being affected by a particular allergen. A diagnosis of allergy is clinical, based on the family history and typical symptoms. Skin tests with allergens are not conclusive. Blood tests may show relative eosinophilia (normal count: 2-4 per cent) and high IgE (normal adult level: upto 120 IU/ml3). These tests are corroborative but not conclusive.
People with allergies do not really outgrow them. They suffer intermittently life long. Allopathic medication and lifestyle changes control the symptoms but do not offer a permanent cure. Frustrated and disappointed, patients may move towards unproven, expensive treatments like provocation testing and neutralisation. Quacks may administer monthly injections of long-acting high-dose steroids as a “miracle” cure. Both these alternatives are dangerous. Yoga and acupuncture are harmless, and in conjunction with medication may offer some benefit.
Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at firstname.lastname@example.org