Allergies are the result of the immune system's mistaken reaction to a harmless substance. Here are signs and symptoms of allergic reactions.

Allergic reactions are sensitivities to substances called allergens that come into contact with the skin, nose, eyes, respiratory system, and gastrointestinal tract. They may be breathed into the lungs, swallowed, or injected. An allergic reaction to food can affect your skin, the gastrointestinal tract, the respiratory system, and, in the most serious cases, the cardiovascular system.

Allergies are the result of the immune system’s mistaken reaction to a harmless substance. Normally, the immune system stands guard and defends the body against intruders that can be dangerous for your health, such as viruses and bacteria. These substances are known as allergens, and when your body reacts for them, it causes an allergic reaction. Here are signs and symptoms of allergic reactions.


  • Allergic reactions are common. The immune response that triggers an allergic reaction is similar to the response that triggers hay fever. Most reactions happen right after contact with an allergen.
  • Many allergic reactions are mild, while others could be severe and life-threatening. They can be limited to a small area of the body, or they might affect the entire body. The most severe form is known as anaphylaxis or anaphylactic shock. Allergic reactions occur more regularly in people who have a family good reputation for allergies.
  • Substances that don’t bother many people can trigger allergic reactions in certain people.
  • Although first-time exposure may produce a mild reaction, repeated exposures can lead to more serious reactions. Once a person has had an exposure or an allergic attack, even a limited exposure to a very small amount of allergen can trigger a serious reaction.
  • Most severe allergic reactions occur within seconds or minutes after contact with the allergen. However, some reactions can happen after several hours, particularly if the allergen leads to a reaction after it has been eaten.

Signs and Symptoms of An Allergic Reaction

Signs and symptoms of an allergic reaction include any, some, or many of the following:

  • Skin: Irritation, redness, itching, swelling, blistering, weeping, crusting, rash, eruptions, or hives (itchy bumps or welts)
  • Lungs: Wheezing, tightness, cough, or shortness of breath
  • Head: Swelling or bumps evidently and neck, eyelids, lips, tongue, or throat, hoarseness of voice, headache
  • Allergic Reaction Symptoms

    Allergic Reaction Symptoms

    Nose: Stuffy nose, runny nose, sneezing

  • Eyes: Red (bloodshot), itchy, swollen, or watery or swelling of the area around the face and eyes
  • Stomach: Pain, nausea, vomiting, diarrhea, or bloody diarrhea
  • Other: Fatigue, sore throat