Clinical symptoms of allergies are itchiness, reddish in the skin, small spots evenly throughout the body or full-swollen bumps with a higher level of skin around,incurred after a person eats food or come into contact with a particular material.
Allergies can be caused by food and also various other causes of substances such as weather, dust, and so on. Allergies are caused by food or other causes can spur the immune system to fight it and produces histamine (a type of compound amino are involved in local immune responses, in addition, these compounds also plays a role in the setting of physiological function in the stomach and as a neurotransmitter) and other chemicals in the body.
This is what finally led to the rejection of the body, a runny, itchy eyes, dry throat,itching and redness of the skin rash, nausea, and diarrhea.
Signs

Skin feels itchy, itchy in good light or heavy. In addition to itching, skin rash, eczema is also experiencing redness, or Buran.
Thickened lips, face and other body parts look swollen.
Sneezing, difficult breathing, and runny.
Abdominal pain, diarrhea, nausea, and vomiting.
Headaches and blurred view.
Fast heartbeat, there was a shock, a severe drop in blood pressure, and loss of consciousness.
The cause of
Allergens on everyone varies, but a reaction caused by the allergy is relatively the same. The following are some causes of allergies.
Food. Usually foods that can cause allergies is a food containing high protein, such as cow's milk, egg whites, peanut, wheat, soy beans, corn, beans, fish, shrimp, squid, shellfish, and others.
Dust and animal dander.
Cold or hot.
Formalin.
Pollen from flowers.
Mushrooms.
Certain drugs.
Prevention
For allergies, which is congenital or descendant does not usually can be prevented.
For the common cause of allergies, such as dust or food, can be prevented by abstinence from the allergens.
Use a mask for those allergic to dust or pollen from flowers.
Maintain the cleanliness of the place of residence, home or Office.
Strengthen the immune system of our body with plenty of eating foods that are high antioxidant, such as vegetables and fruits.