What is allergy?
Allergy is an abnormal reaction of the body to a substance, usually a protein. We have antibodies in our body that are produced in response to a trigger, which is called an antigen. Mostly this is protective, for example, antibodies protect us against many diseases including common cold. Some antibodies have to be induced- for example vaccination against small pox or polio. These protect us against such deadly diseases for our whole lifetime.
Similarly, antibodies that develop against substances that cause nasal allergy or asthma remain with us for life. Why they are stimulated to be formed is unknown. Because we cannot undo formation of antibodies, as they are more beneficial than harmful, we can only modify the way in which we react to the allergic reaction. Substance that produce allergy in humans is usually house dust. This is actually the excreta of a tiny insect called house dust mite, which feeds on dead human skin, which we all constantly shed. Other less common allergens are animal hair, pollen and fungus.
What are the symptoms of allergy?
Allergic reactions, though common in the mode of causation, have symptoms depending upon the site of allergy. Since the allergens are usually inhaled, the symptoms affect the nose, throat and the lower airway, the lungs. Nasal allergy causes watering, sneezing, nasal block or thick nasal discharge. Chest allergy causes cough, breathlessness or wheeze. Patients could also have itching of the nose, eyes and throat
How is allergy diagnosed?
Allergy is usually diagnosed with the typical history that the patient describes. There is no specific test for allergy though some prick tests and laboratory diagnostic methods are available, are rarely used for confirming the diagnosis, which is usually straightforward. Nasal Endoscopy, lung function tests and blood tests are used to assess the severity of allergy
Is allergy curable?
No, allergy is not curable, but the symptoms of the disease can usually be controlled, allowing the patient to lead as normal a life as possible. This can mean long-term treatment, but today’s medications have very little or no side effects.
Can allergy be prevented or avoided?
It would be easy, of course, to avoid the allergy causing substance if it could be done. However, it is usually not possible especially in the case of the most common offender, house dust. But by keeping your environment clean and dust free, the intensity of the allergy can be reduced. Some treatment options like desensitization involves using allergens of low potency, in gradually increasing doses, to acclimatize the patient to allergen load. These options are not universally successful in majority of patients, but they are useful additions to treatment options
If allergy cannot be prevented or avoided, how can allergy be controlled?
If the allergy is mild and intermittent, avoiding provocation of allergy and using drugs like antihistamines provide a safe and effective option. Antihistamines are not be given long term- and for such people with persistent or continuous allergic symptoms, inhaled corticosteroids provide the best option. There are also disease-modifying drugs like Montelukast, or Omalizumab which are safe to use.
What are the dangers of using corticosteroids for a long time?
Corticosteroids are present in our own body in significant amounts, and help maintain many important functions of the body. If corticosteroids are taken orally for a long time, this can derange the body’s own production of steroids, and cause problems. These problems are of course, reversible to a large extent. However, in allergy, inhaled steroids are used. These work directly on the air passage and prevent antigen antibody reaction- the main cause for allergy. Since the inhaled steroids are used in such low doses that they do not get into the blood stream, they do not cause any side effects and have been used in millions of patients worldwide for over 30 years without any side effects.
What can happen if allergic symptoms are ignored?
Our airway has mucous gland, which secrete mucus. This acts as a cleaning agent and traps dirt and other matter, to be wiped away by the action of tiny hair like structures called the cilia. These delicate tissues line the entire nasal cavity and the lung passages. Allergic reaction damages this mechanism. Over the years, when the cilia and the mucus blanket ( as they are called) are damaged, the cleaning action is permanently damaged, leading on to irreversible airway disease. The lung and sinuses, which cannot clean themselves, become clogged with thick diseased material and do not function normally. Patients who have long term untreated allergy, suffer from severe conditions like chronic sinusitis or emphysema, and never become entirely normal again.
Is there any way to avoid this alarming picture?
Yes, prompt management of persistent allergy with inhaled steroids happen to be the only proven method now to prevent this damage. Omalizumab, a new drug can also help, but is extremely expensive for routine use.
Does surgery help cure allergic symptoms?
No. Allergy is a medical condition and surgery does not alter or change it. Surgery is used in complications of allergy like polyps, sinusitis or other infections, but only as an adjunct to treatment. Even after surgery, patients are supposed to continue inhaled steroids and other medications. Sometimes a badly deflected nasal septum can prevent the nasal spray being used properly and is to be straightened by surgery, although this is not very effective for long-term control of symptoms.
Are steroid inhalers safe for children and elderly, and those with chronic diseases like diabetes or high blood pressure ?
Yes, children over 2 years of age can safely use inhaled steroids, and so can the others. They are also safe in pregnancy and breast feeding.
Does this all mean that you have to see a doctor for life?
No. Your doctor who is skilled in treating allergy will teach you how to adjust your inhaler use to control your symptoms. He will teach you how to reach at that minimum required dose. There are aids like a peak flow meter, for example, which can be used to measure asthmatic patients airflow through the lungs. The patient does this at home, and drugs are modified according to the airflow volume in the lung, which is a direct indicator of health. Soon the patient, instead of letting allergy control him or her, learns to control allergy, and starts leading as normal a life as possible.