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Drug Allergy


  • Adverse reaction is the medical term for any undesirable reaction caused by a medication. Both allergic and nonallergic adverse reactions can occur.
  • Make sure you inform your child’s doctor upon each visit if he/she suffers from a drug allergy, and the type of symptoms they experience.


Drug Allergy : Another form of allergy that parents must be aware of.

Adverse reactions to medication that include the following predictable and unpredictable behaviors:

  • Predictable reactions: Occur as a result of the medication’s side effects, for example, drugs used to reduce runny nose could result in the child feeling sleepy, or other types of drugs may produce unwanted reactions when used alongside one another. Additionally, some predictable reactions occur due to the amount of medication being used.
  • Unpredictable reactions: Includes drug allergies that occur as a result of the body’s immune system reacting to the medication or ingredients used in the drug, which stimulate the body’s chemical production to defense the drug or ingredients. The symptoms may differ from case to case.

Although drug allergies only account for a small fraction of these unwanted reactions, such symptoms are crucial because they can be potentially fatal if the person suffers from anaphylaxis.

Drug allergies can flare up any time the child receives a certain form of medication, with such reactions occurring either immediately after the drug has been administered, or a short period of time later.

* Drug allergies do not necessarily occur the first time a child is exposed to a certain form of medicine. Some symptoms may only present themselves after a few exposures to medication.

Symptoms of a drug allergy:

  • Skin rash or hives
  • Itchiness
  • Wheezing, difficulty breathing or breathlessness
  • Angioedema
  • Hypotension
  • Anaphylaxis

Aside from the aforementioned symptoms, there are other more serious symptoms of a drug allergy that tend to occur after prolonged exposure to the medication, over a period of days or weeks, such as:

  • Serum sickness, which may cause fever, joint pain and a rash
  • Toxic Epidermal Necrolysis and Stevens – Johnson syndrome, which may cause a form of a severe rash that may involve shedding of the skin, blister on mucous membrane
  • Drug reaction with eosinophilia and systemic symptom, which result in rash that occurs in conjunction with other symptoms, such as a fever and inflammation of lymph node, kidneys and liver.

Common forms of drug allergy

  • Penicillin and related antibiotics
  • Antibiotics containing sulfonamides (sulfa drugs)
  • Anticonvulsants
  • Aspirin and non-steroidal anti-inflammatory medication (NSAIDs)
  • Anesthetic drug
  • Chemotherapy medication

Diagnosing a drug allergy:

  • Inquiries will be made about past use of medication: when the patient was given medication and the symptoms displayed, which medication they’ve been prescribed in the past, and any history of allergic reactions.
  • Physical examination
  • Skin prick test (highly accurate when used in the diagnosis of an allergy to Penicillin)
  • Drug challenge test

Treating a drug allergy

  • Avoid medication causing the allergy.
  • Take anti-allergy medication to control the symptoms.
  • If you suspect your child has a drug reaction, see your pediatrician or an allergist immediately

Your child does suffer from a drug allergy

  • Remember to inform doctors and medical staff of the drug they are allergic to as well as the symptoms they usually suffer from, each and every time they are taken in for treatment.
  • Ask your doctor or pharmacist whether there are any other similar drugs which should also be avoided.
  • Ask your doctor or pharmacist about other similar drugs which can be used instead of the medication which causes your child’s allergy.
  • Ensure that your child has an allergy card with them at all times to inform doctors or pharmacists of the substances they are allergic to.

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Buntita Bamrungchaowkasem, M.D. Summary: Pediatrics Pediatric Allergy And Immunology