Sometimes medicines used to treat an illness cause reactions, which could be due to a medication allergy or drug allergy. These allergic reactions usually involve the skin, but there are a number of ways that medication allergy can cause symptoms in your child. Antibiotics are the medicines that most often cause allergic reactions.
Doctors classify allergic reactions to medications by how they occur. There are four types of allergic reactions:
- Type I reactions. Type I reactions happen as soon as a child is exposed to the medicine. Symptoms may include anaphylaxis, hives or swelling, digestive symptoms like vomiting and diarrhea, wheezing or sneezing.
- Type II reactions. Type II reactions may cause anemia, a condition in which the body does not have enough healthy red blood cells. This type of reaction is rare.
- Type III reactions. Type III reactions are known as serum sickness (an allergic reaction to an injection of serum). Symptoms include hives, fever, joint pain and swollen glands.
- Type IV reactions. Type IV reactions cause contact dermatitis (a rash that resembles poison ivy).
It is important for you to know the type of reaction your child has, because some reactions can be life-threatening, and your child may be exposed to the same medicines in the future. Serious, life-threatening allergic reactions usually occur within a few hours after the first dose.
Sometimes in children, there can be an interaction between a virus and a medicine. It may appear to be an allergy when it is only an interaction between the virus and the drug. If a rash or other type of skin reaction occurs, your child's doctor can help classify the type of rash. Skin reactions that are a concern are hives, which are raised areas of skin that are itchy and typically last less than 24 hours if due to allergy. Let your child’s doctor know if he or she exhibits a reaction.
Diagnosis of Medication Allergy
As with all allergies, your child’s health history and a physical exam are the most important pieces of information needed to diagnose a medication allergy. Allergy specialists at Riley at IU Health may also use a type of allergy test called a skin test. Skin tests can be performed for penicillin and penicillin-related medicines. An allergist can also test for local anesthetics and insulin allergy.
Sometimes allergists use drug challenges to confirm a medication allergy diagnosis. A drug challenge involves giving small doses of a suspected allergenic medicine to your child to see if a reaction occurs. Allergists at Riley at IU Health perform drug challenges in a special, controlled environment so your child can be carefully monitored during the challenge and treated immediately if a reaction occurs.
At the time of the reaction, your child’s doctor will provide care depending on the type of reaction. Treatment guidelines for a medication allergy may include:
- Consult your child’s doctor about possibly stopping the medicine—this is very dependent upon your child’s symptoms and when the reaction started (early or late in the course of treatment with the medicine). Ask if a different medicine could be an option for your child.
- Use an antihistamine to treat any itchy rash.
- Seek medical care at a clinic or emergency department if your child is experiencing a severe reaction such as anaphylaxis.
If there are no other choices for medicine and your child’s history shows that certain medicines are the reason for the allergy, then desensitization will likely be required.
Desensitization means that small doses of the medicine are given to your child. Over time, more medicine is given until the highest dose (the one that your child can tolerate without a severe allergic reaction) is reached.
Desensitization can be a long process. When desensitization works, the medicine must be used on a daily basis to maintain the desensitized condition.
Key Points to Remember
Key Points to Remember
- Sometimes medicines used to treat an illness cause allergic reactions.
- Antibiotics are the medicines that most often cause allergic reactions.
- Doctors classify allergic reactions to medications by how they occur.
- The most common treatment for medication allergy is for the doctor to prescribe a different medicine, but if there is no other medicine your child can take, desensitization may be needed.
Support Services & Resources
Support Services & Resources
Visit the trusted websites below to learn more about medication allergy.
Riley at IU Health offers a broad range of supportive services to make life better for families who choose us for their children's care.
The American College of Allergy, Asthma & Immunology provides in-depth information about drug allergies.
This website provides more information about adverse reactions to medicines.
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