Allergy

An allergy is an exaggerated immune response or reaction to substances that are generally not harmful. Among people of all races in the U.S., the highest food allergy rates were reported among children under the age of 18 (7%). Adults over the age of 60 had the lowest rates (about 1%).

About 5.6 million children under the age of 18 in the U.S. have food allergies, according to FARE (Food & Allergy Research Education), and African-American children in the U.S. have a higher rate of food allergies than children of other races.

According to a study published in the March issue of Annals of Allergy, Asthma and Immunology, the scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI), self-reported food allergy nearly doubled in black children over 23 years at a rate of 2.1% per decade.

Causes

Allergies are pretty common. Both genes and environmental factors play a role. The immune system normally protects the body against harmful substances, such as bacteria and viruses. It also reacts to foreign substances called allergens, which are generally harmless and in most people do not cause a problem.

But in a person with allergies, the immune response is oversensitive. When it recognizes an allergen, it releases chemicals such as histamines. which fight off the allergen. This causes allergy symptoms.

Common allergens include:

• Drugs
• Dust
• Food
• Insect bites
• Mold
• Pet dander
• Pollen

Some people have allergy-like reactions to hot or cold temperatures, sunlight, or other environmental triggers. Sometimes, friction (rubbing or roughly stroking the skin) will cause symptoms.

A specific allergy is not usually passed down through families (inherited). However, if both your parents have allergies, you are likely to have allergies. The chance is greater if your mother has allergies.

Allergies may make certain medical conditions such as sinus problems, eczema, and asthma worse.

Symptoms

Allergy symptoms 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

The part of the body the allergen touches affects what symptoms you develop. For example: