Drug allergy testing services

In order to get your child a correct diagnosis about drug allergies, we may use different approaches, including:

• Allergy tests, such as skin testing (also called prick testing), in which a tiny amount of a drug is administered to the skin to see how your child reacts. A positive reaction can cause a red, itchy bump.

• A challenge test, which typically consists of giving one or two doses of the medication in increasing amounts. 

Pinpointing the causes of pediatric drug allergies 

Our team includes UT Southwestern physicians who are among the nation’s top experts in drug allergies. We see more patients with drug allergies than almost any other program in the region. This gives us the experience and expertise to understand your child’s allergy.

To treat and manage a drug allergy, it is very important to have an accurate diagnosis. We begin our evaluation with a detailed history of any reactions your child has had to medications in the past. We will also give your child a physical exam. For the medical history, it’s helpful if you can give details about:

• What medications your child took and what the dose was

• How long they took them

• What symptoms they had

• When the symptoms occurred

• How long they lasted

• What other prescriptions, over-the-counter medications or herbal supplements your child also takes

• What other allergies your child may have – including to drugs, food and insects

• Whether there is a history of allergies, including food allergies, in your family

Understanding allergic reactions to medication

At the Drug Allergy Program, one of our first goals is to figure out what kind of reaction your child is having to a medication. We carefully evaluate your child’s past reactions and monitor any new reactions they might be having. This helps us understand the underlying cause to their reactions and develop a plan to manage it.

A drug allergy happens when your child’s immune system recognizes and responds to a drug. There are many ways the immune system can respond to things that are not a part of the body. The way the immune system responds to a drug determines the type of allergy and the symptoms it can cause. This abnormal immune response can affect almost any organ in the body, depending on the type of immune response your child’s body has toward the drug. The term “hypersensitivity” is often used to describe these drug allergy reactions. In addition, your child can have reactions that are not caused by the immune system. These reactions can include intolerance, side effects or toxic effects from the medication. Our Drug Allergy Program can help to distinguish these drug reactions from reactions caused by the immune system.

Managing the most common pediatric drug allergies

Our program sees children with rare allergies, as well as many children with common drug allergies. We have extensive experience with different strategies to manage these allergies. We also collaborate with our colleagues at Children’s Health to recommend alternative drugs that could help your child, without causing an allergic reaction. Some examples of drug allergies that our program manages include:  

• Penicillin allergies

• Other antibiotic allergies

• Vaccine allergies

• Perioperative reactions, which occur in response to drugs during surgery

• Reactions to biologics, such as monoclonal antibodies, which are used to treat many diseases, including some cancers

• Reactions to chemotherapy in cancer treatment 

Drug desensitization for children

In some children with drug allergies, we are able to use a process called desensitization to help them tolerate the medications they need. This process involves giving very small doses of the medication to your child, and gradually increasing those doses over time. This can teach your child’s body to tolerate a medication, so they can safely receive it. 

How do you know if you or your child is allergic to medication?

Reactions to medications can range from mild to severe. If your child develops some of these symptoms either immediately after taking a drug or within days or a few weeks, they may have had an allergic reaction. Symptoms include:

• Rapid onset of hives, itching, swelling, wheezing, shortness of breath

• Fevers, joint swelling or pains

• Rash

• Drug-induced anaphylaxis, which is a serious allergic reaction that can affect different systems and be life threatening

• A spectrum of rare, serious skin reactions called severe cutaneous adverse reactions, which include:

  • Drug-related eosinophilia with systemic symptoms (DRESS), which leads to a rash, swelling, swollen lymph nodes and a high count of white blood cells

  • Acute generalized exanthematous pustulosis (AGEP), which causes swelling, red bumps on the skin and usually a high count of white blood cells

  • Severe blistering diseases such as Stevens Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), which can also affect other organs and require ICU-level care. Patients with HIV/AIDS and lupus are typically at risk.

Some reactions appear quickly, and some may not show up for days or weeks after a child is exposed to a drug. Some reactions last a few hours, while severe ones may persist.