Allergic Reactions

What Is An Allergic Reaction?

An allergic reaction is caused by an overreaction of the body's immune system. In some individuals, the body creates antibodies to things that are usually harmless to the body and the reaction causes anything from mildly annoying symptoms to sudden and life threatening symptoms. The allergens come in a wide variety and can come in contact with the skin, nose, eyes, respiratory tract, or gastrointestinal tract. One can breathe, swallow, or receive the allergen via injection. They can affect a small area of the body or affect the entire body. The reaction is usually immediate and if life threatening requires fast medical attention.

Mild Allergic Reactions

  • Hives (esp. neck/face)
  • Itching
  • Nasal congestion
  • Rash
  • Watery, red eyes

Moderate/Severe Reactions:

  • Abdominal pain
  • Abnormal breathing
  • Difficulty breathing
  • Anxiety
  • Chest discomfort or tightness
  • Cough
  • Diarrhea
  • Difficulty swallowing
  • Dizziness or light-headedness
  • Facial flushing
  • Nausea or vomiting
  • Palpitations
  • Swelling of the face, eyes, tongue
  • Unconsciousness
  • Wheezing

Common Types of Allergens:

  • Food Allergies: especially nuts, fish, and shellfish. More common in children than adults, more common in those with asthma or other allergies.
  • Medicine Allergies: common and unpredictable, severity varies, could be swallowed, injected, or applied topically
  • Insect bites/bee stings: anything beyond localized swelling and redness could be an allergic reaction
  • Animals: dander (pet’s dead skin), urine, dried saliva, and hair are known to be allergens
  • Latex/cosmetics: some things that come in contact with the skin trigger allergic reactions
  • Inhaled substances: pollens, dust, workplace exposures, are known to cause allergic reactions when breathed in


Mild Reaction: Identify and avoid the allergen if possible. If stung, remove stinger whole by scraping (do not squeeze with tweezers, more venom can be released that way). Wash area with soap and water. For a rash, a cool compress and hydrocortisone cream can be helpful. Antihistamines can be considered. Control anxiety.

Severe Reaction: Check the person’s breathing and if necessary, begin rescue breathing/CPR. Call 911, promote calmness, remove stinger if stung, administer emergency allergy medication (i.e. epinephrine pen) if available, and take steps to prevent shock. These include lying the person flat (no pillow) with feet raised 12 inches and cover with coat or blanket. Don’t administer oral medications if the person is having difficulty breathing.

Allergy Shots: Allergy testing is available through an allergist, and some choose to receive allergy shots on a monthly basis to develop a tolerance to certain allergens. This treatment requires careful monitoring for reactions in the doctor’s office.

Medline Allergic Reactions

WebMD What is an Allergic Reaction?