Allergies are relatively common. Both genetics and environmental factors are responsible for allergies. Our immune system protects the body from harmful substances, like bacteria and viruses. It also protects from foreign substances called allergens, which are generally harmless and in most people do not cause a problem.

Person with allergies are oversensitive to the immune response. When it recognizes an allergen, system releases chemicals such as histamines. which fight off the allergen which may cause itching, swelling, mucus production, muscle spasms, hives, rashes, and other symptoms. It vary from person to person. Common allergens include pollen, mould, pet dander, and dust. Food and drug allergies are also common. Allergic reactions can also be caused by insect bites, jewellery, cosmetics, spices, and other substances. Some people are sensitive to hot or cold temperatures, sunlight, or other environmental triggers. Rubbing skin may also cause symptoms.

Allergy may be inherited. If both of your parents have allergies, you are likely to have allergies. The chances are greater if mother has allergies. Allergies may cause sinus problems, eczema, and asthma worse.

Allergy symptoms vary, but may include:

• Breathing problems (coughing, shortness of breath)
• Burning, tearing, or itchy eyes
• Conjunctivitis (red, swollen eyes)
• Coughing
• Diarrhea
• Headache
• Hives
• Itching of the nose, mouth, throat, skin, or any other area
• Runny nose
• Skin rashes
• Stomach cramps
• Vomiting
• Wheezing

What part of the body is contacted by the allergen plays important role in the allergy symptoms.