Allergies are seen in form of watering of eyes (allergic conjunctivitis) running nose (allergic rhinitis), breathlessness and cough (asthma), skin rashes -wheals and urticaria (allergic dermatitis) and diarrhea (colitis).

Are allergies contagious?

Allergies are not contagious as they are due to aberration in the body's immune system. Hence they cannot be transmitted from one person to the other.


Heredity can play some role in allergies. If one parent has an allergic disease, chance of a child developing allergies is 25% and if both parents have allergies, then chances of a child developing allergies is 50%. However, allergies may not be present at birth and can develop at any age.


This is due to a unique immune system in every individual. When the body comes in contact with an allergen for the first time, the immune system considers it harmful and forms antibodies against it. When the body comes in repeat contact with the allergens, then more antibodies especially an antibody called as IgE is formed that leads to various reactions. IgE releases chemical called histamine that causes swelling, redness, inflammation in organs such as nose, eye, skin, lungs leading to symptoms.


Smoke, dust, pollen, chemicals, fungi, nuts, beans, potatoes, carrots, lobsters, crabs, shrimps, milk, plastic, drugs such as penicillin and insect bites can lead to allergies in an individual who is prone to allergies.


Some patients have allergies throughout the year (perennial allergies) as seen with dust mites which may be present in carpets and mattresses or some may get symptoms only with particular season as seen with allergies to pollen.