Drug Allergies Specialist

DFW Asthma & Allergy Center

Allergy & Immunology located in Plano, TX

Though drug allergies are rare, all types of drugs can potentially cause an allergic response, including a life-threatening anaphylactic reaction. You receive comprehensive care for drug allergies from Aasia Ghazi, MD, at DFW Asthma & Allergy Center. Dr. Ghazi performs allergy testing and creates individualized treatment plans that protect your wellness while also helping you tolerate the medications essential for your health. If you suspect you experience a reaction after taking medications, don't wait to get a complete evaluation. Call the office in Plano, Texas, or book an appointment online today.

Drug Allergies Q&A

What causes drug allergies?

In most cases, if you have a reaction to a drug, it’s a side effect, not an allergic response. However, 5-10% of all drug reactions occur due to an allergy.

When you have a drug allergy, your immune system releases chemicals in response to the medication. The chemicals then cause your allergy symptoms.

Any medication could cause an allergy, but the most common drug allergies include:

  • Antibiotics such as penicillin
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Anti-seizure drugs
  • ACE inhibitors
  • Monoclonal antibodies
  • Chemotherapy medications

If you have an allergy to one drug, you have a higher risk of developing an allergy to other medications.

What symptoms develop due to drug allergies?

Drug allergy symptoms often occur within hours to two weeks after you take the medication. However, some medications cause a delayed reaction, such as a skin rash that occurs in about six weeks.

When symptoms appear, you may experience any of the following:

  • Hives
  • Skin rash
  • Cough
  • Sneezing
  • Runny or congested nose
  • Itchy, watery eyes
  • Nausea and vomiting
  • Diarrhea
  • Headaches


Drug allergies can also cause a severe, life-threatening reaction called anaphylaxis. Anaphylaxis typically occurs within an hour of taking the medication, causing symptoms such as hives, itching, and swelling of your lips, tongue, throat, or face, difficulty breathing, dizziness, and fainting.


Anaphylaxis requires an immediate injection of epinephrine and emergency medical care to prevent shock and death.

How are drug allergies diagnosed and treated?

DFW Asthma & Allergy Center tests for drug allergies, including a penicillin allergy, using a skin prick, intradermal, or blood test. If these tests produce uncertain results, your provider may recommend a graded challenge.

During a graded challenge, your provider gives you several doses of the drug, beginning with a small amount, and gradually increases each dose. If you reach the full therapeutic dose without having a reaction, you're not allergic to the medication.

Your treatment plan may include medications such as antihistamines to ease your symptoms or steroids to reduce inflammation. However, the primary treatment is to avoid taking the medication.

If you need the medication for a health condition, your provider may recommend drug desensitization, a technique frequently used for aspirin and antibiotics. During this treatment, you receive doses of the drug, beginning with a very small dose, and then get progressively larger doses every 15-30 minutes.

The treatment continues for several hours or days, slowly desensitizing your immune system. If you reach the full dose without having a reaction, you can safely take the medicine.

To get help for a drug allergy, call DFW Asthma & Allergy Center or book an appointment online today.