Allergies are an immune system response to substances that the body perceives as dangerous. According to the Mayo Clinic, food allergies occur in 6 to 8 percent of children under 3 and in 4 percent of adults. The most common food allergies are nuts, peanuts, shellfish, fish, milk, eggs, wheat and soy. Allergy symptoms can be mild to severe and can appear within minutes to a few hours after being exposed to an allergen. Food allergies cannot be cured, and the only way to prevent a reaction is to avoid the allergen.
Facial Symptoms
An allergic reaction can cause the mouth to tingle. It also can cause the lips, face, tongue and throat to swell. Severe swelling can lead to breathing problems.
Respiratory Symptoms
Wheezing, congestion, shortness of breath, difficulty breathing, asthma and runny nose are all symptoms of an allergy.
Skin Symptoms
According to Merck Manuals, skin rashes like eczema and hives are usually the first symptoms of an infant food allergy; however, rashes due to food allergies usually subside by age 1. Hives, eczema and itching also can affect adults with food allergies.
Additional Symptoms
Adults and infants with food allergies may experience nausea, vomiting, diarrhea and abdominal pain. Food allergies can cause dizziness, light-headedness and fainting.
Anaphylaxis
Anaphylaxis is a very serious allergic reaction. According to the Food Allergy and Anaphylaxis Network (FAAN), food allergies are the No. 1 cause of anaphylaxis outside the hospital, and between 50,000 and 125,000 emergency room visits per year are the result of anaphylaxis. It can begin within minutes of exposure to an allergen and continue to worsen over several hours.
Tingling and itching of the mouth are the first noticeable symptoms, progressing to hives, wheezing and coughing, swelling of the mouth and throat, vomiting, diarrhea, cramps, extremely low blood pressure and loss of consciousness. In some cases, anaphylaxis can be fatal. People with a history of anaphylaxis, family history of allergies and those with both asthma and allergies are more at risk for anaphylaxis and should wear medical identification. Anaphylaxis is treated with epinephrine, a drug that relaxes airway muscles and tightens blood vessels.
