Drug Allergy

Do you suffer from skin irritations such as itchiness, rashes and hives, but have no idea what is causing them after taking certain medications?

Unbeknownst to many, the underlying causes of allergies differ from individual to individual. The three most common allergies are contact allergy, food allergy and drug allergy.

What is Drug Allergy?

A drug allergy is the reaction of the body’s immune system to a particular medicine. When this happens, the immune system treats the drug as a threat to the body, releasing chemicals that induce symptoms of an allergic reaction.

All types of medicine, whether prescribed or herbal, can cause a drug allergy. Some medicines are more prone to causing drug allergies.

Common causes of Drug Allergy in Singapore?

Consuming certain drugs can trigger allergies in some individuals. Common drugs that cause allergies include:

• Drugs prescribed to treat seizures
• Antibiotics (especially penicillins)
• Nonsteroidal anti-inflammatory drugs (NSAID) like voltaren, aspirin
• Medications containing sulfur
• Chemotherapy drugs

What are the symptoms of Drug Allergy?

The symptoms of drug allergy vary from each individual, and can occur immediately or after a few weeks. These are some common symptoms:

• Itchy and red eyes
• Skin rashes or hives
• Mouth and skin ulcers
• Wheezing and congestion of the nasal passages
• Shortness of breath
• Abdominal cramps, nausea and vomiting

Drug allergies can also trigger a serious allergic reaction called anaphylaxis. This requires urgent medical attention. These are the symptoms of anaphylaxis:

• Tightening of airways
• Swollen throat and difficulty breathing
• Severe drop in blood pressure and rapid pulse
• Feeling dizzy, lightheaded or losing consciousness

Are Drug Allergies serious?

Drug allergies can be serious and life-threatening. They usually manifest as hives, fever, and rashes, leading to inflammation and redness. However, occasionally they can cause serious illnesses requiring intensive care stay in the hospital. They can be life threatening when the airway is compromised and patients cannot breathe properly.

Who is at risk of Drug Allergy in Singapore?

While anyone can develop a drug allergy at any age, there are some factors that put you at a higher risk.

• Increasing age
• A personal or family history of drug allergies or other allergies
• Having illnesses such as asthma, human immunodeficiency virus (HIV), Epstein-Barr virus (EBV), and cancer
• Repetitive use of a particular drug especially in increasing doses
• Administration of a drug (topical or intravenous)

How are Drug Allergies diagnosed?

Drug allergies may be diagnosed based on your symptoms alone, or your dermatologist may suggest tests to determine the source (or sources) of your allergy.

• Skin prick test - A tiny amount of the suspected drug is placed on your skin, and then your doctor will prick the skin with a needle to enable the substance to enter the surface of your skin. If you develop a bump or irritation, it indicates an allergy to the drug.
• Blood test - Blood samples may be taken to rule out other illnesses that may be causing the allergic reaction.

What are the treatment options for Drug Allergy in Singapore?

Treatment options for drug allergies in Singapore vary, as it depends on how severe your reactions are and how important the drug is to your well being. Once the drug allergy has been identified, you should avoid the culprit drug to prevent further allergic reactions and look for suitable alternatives. Always inform your healthcare providers and doctors if you have a diagnosed drug allergy.

These are some common treatment options for drug allergy:

• Withdrawal of the drug that is causing the allergy
• Antihistamines
• Medication to treat anaphylaxis
• Corticosteroids - either oral or topical