Allergy is the abnormal reaction of our immune system to substances like dust, moisture, animal dander, pollen etc that are usually harmless. Substances which cause allergies are known as allergens.

How allergic reactions are caused?

When a person is exposed to an allergen by swallowing of inhaling or through skin a series events takes place which constitutes an allergic reaction.

1)      The body produces an antibody named IgE to contain the allergen. These antibodies attach to a group of blood cells called mast cells. Mast cells are usually found in the airways, gastrointestinal tract etc. which make these areas susceptible to allergies. The allergens get binded to the IgE in the mast cells causing the mast cells to release various chemicals into the blood. Most of the symptoms of the allergies are produced by histamine which is the main chemical released in an allergic reaction.

Symptoms of allergic reactions

1)      Sneezing

2)      Watery, itchy eyes

3)      Rashes

4)      Runny nose

5)      Feeling ill or tired

 Allergic diseases first appear in children as food allergies or atopic dermatitis (eczema). These children are more prone to allergies like rhinitis and asthma in their school age. Most of the food allergies and atopic dermatitis goes away as they grow up. But allergies like asthma and rhinitis are likely to continue throughout their life time. But the allergic symptoms may temporarily disappear for some time.

Atopic dermatitis

Symptoms of this allergy are shown in about 20 % of all infants.  This disease is characterized by itching and rash formation. The rashes are red and dry and may ooze over time. In  young children these rashes are commonly found on face, neck, back of scalp, chest, trunk, arms and legs.

Food allergies

Food allergies are found in people of all ages. When people with food allergy eat the allergic food material itching, swelling of redness appear in the skin within a few minutes of eating. Diarrhea, vomiting, stomach aches, breathing difficulties, runny nose, sneezing etc are the symptoms of food allergy. Some children may experience life threatening reaction called anaphylaxis.

Nasal allergies

Rhinitis is the name of the common nasal allergy found in 40 % children and 30 % adults. Itchy nose and eyes, runny nose, nasal congestion etc are common symptoms. Post nasal-drip is experience by some persons.  Rubbing the nose with palm may cause the formation of a line on the nose known as allergic salute is a symptom of this disease.


Asthma is a disease found in 80 % of the people and the main cause for asthma is allergic reaction. It normally starts in females in their teen ages and in males in their pre teen ages. Coughing which increases when allergic reaction triggers, wheezing which is a high pitched music note produced while inhaling, Shortness of breath when the allergic reaction triggers or when engaged in physical activity, tightness in chest etc. are the major symptoms of asthma.


There are a number of over the counter medications that can give relief from the annoying symptoms. They are detailed below.

Antihistamines: Antihistamines stop or reduce the production of histamines which is the main chemical released in allergic reactions. Antihistamines are available in the form of tablets, capsules, nasal sprays ear drops etc. Some antihistamines are sold on prescription only.

Decongestants: Decongestants are used to clear a blocked nose as a result of allergic reaction. Decongestants are available in the form of nasal sprays, nasal dips and pills. Using nasal sprays for more than 3 days may increase your nasal congestion.

Anticholinergic nasal sprays: These nasal sprays help to reduce the secretions glands in the nasal passage. Excess usage of Anticholinergic nasal sprays can cause dry nose which may result in bleeding also.

Steroid nasal spray: Steroid nasal sprays help to reduce the inflammation in nasal cavities. Sore throat and nose bleeding are the common side effects of steroid nasal spray

Eye drops for allergic reactions

Different type of eye drops are available which can be used get relief from the symptoms of  allergic reactions. Some of them are sold over the counter and some others need physician’s prescription. It has to be understood that the eye drop intended for itching of eyes may not be suitable for red eyes.

Leukotriene inhibitors: These are drugs used  to control asthma symptoms as it helps to keep the airways  open. This is a prescription medicine and its side effects are headache, earache, sore throat, nausea etc.

Mast cell inhibitors: Cromolyn sodium is a commonly  used mast cell inhibitor to prevent symptoms like runny itchy eyes or  nose.