Medicine Allergy Definition, Reason, Diagnosis, Symptom, Treatment

Drug allergy is a condition when a person experiences various symptoms after getting certain drugs, either oral or topical drugs

Drug Allergy Definition

Drug allergy is a condition when a person experiences various symptoms after receiving certain drugs, either oral, topical, or injectable drugs.

Several risk factors make a person more prone to drug allergies, namely:

  • Have a history of allergies, such as food allergies
  • History of drug allergy in the family
  • Long-term use of the drug, high doses, or repeated use
  • Presence of certain diseases related to drug allergies, such as HIV


Drug allergies occur because the body mistakenly recognizes which is ‘foe’ and which is ‘friend’. Drugs that enter or are exposed to the body are considered harmful substances and need to be fought, just as the body fights viruses and bacteria.

Drug allergies are more common when a person takes certain medications, for example:

  • penicillin
  • sulfa class of antibiotics
  • anti-seizure
  • aspirin, ibuprofen and non-steroidal anti-pain medication
  • chemotherapy drugs


The diagnosis of drug allergy is determined on the basis of complaints after using certain drugs. At the initial examination, the doctor will conduct a complete and thorough medical interview regarding the symptoms that arise, as well as the type and amount of medication that has just been taken or applied to the skin. In addition, a physical examination will be carried out to determine the various symptoms of allergies experienced.

This diagnosis is confirmed by various additional tests, such as:

  • Skin Test

The skin test is done by injecting a small amount of medicinal extract into the skin layer. If the results of this injection turn into redness and swelling, the prick test is read as positive for drug allergy. If no reaction occurs, drug allergy also cannot be ruled out. The results of other tests must first be seen.

  • Blood test

Blood tests are done to rule out other diseases or conditions that can mimic a drug allergy, such as a viral infection.


Mild symptoms of drug allergies such as skin redness generally occur within hours to days. However, severe symptoms such as shortness of breath can occur within 1 hour after drug exposure.

Symptoms that can occur include:

  • red rash on skin
  • itchy rash
  • fever
  • swelling in the eyes and body
  • hard to breathe
  • runny nose
  • itchy and watery eyes

In severe cases, drug allergies can cause a fatal reaction called anaphylaxis. Signs of a person experiencing an anaphylactic reaction are as follows:

  • sudden shortness of breath
  • severe stomach pain
  • very fast heart rate
  • convulsions
  • loss of consciousness due to a drastic drop in blood pressure


Drug allergies can be overcome by avoiding consumption of the type of drug that triggers it and other drugs that have the potential to be allergic because of the similarity of the basic ingredients. Always ask the treating doctor, the type of drug that should be avoided.

If an allergic reaction has already occurred, the treatment that can be given generally includes the administration of an antihistamine to suppress the body’s allergic response.

Anaphylactic reactions should be treated immediately with epinephrine or adrenaline to avoid fatal consequences. A life-threatening anaphylactic reaction is the most serious effect or complication of drug allergy.

Actions in the form of drug desensitization can be done by doctors to reduce the level of allergic sensitivity experienced. Gradually, drugs that have the potential to cause allergies will be given. Start with the lowest dose. If there is no reaction, slowly increase the dose. However, desensitization must be carried out under the close supervision of a doctor, considering that allergic reactions can occur at any time.


Prevention of drug allergic reactions can be done by knowing for sure the type of drug that triggers the allergy. Always inform this to medical personnel every time an allergy sufferer is treated. This is done so that the drug given is then free from ingredients that can trigger an allergic reaction.

In addition, a person who has a drug allergy is expected to wear an ‘allergy bracelet’ that lists the types of drugs to avoid. In an emergency, the bracelet can provide information at any time which prevents a patient from having a dangerous allergic reaction.

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