The world is filled with potential allergens ranging from peanuts and medications to pollen and pet dander. Unfortunately, you don’t always know which substance is causing your allergy symptoms. That’s where allergy tests come in.
When you schedule your allergy test, we’ll give you information about which medications you can and can’t take. If you’re taking a skin allergy test, the primary medication group to avoid is antihistamines.
What Are Antihistamines?
When you encounter a substance that you’re allergic to, your body releases a chemical called histamine. Histamine causes allergy symptoms like hives and sneezing[1].
Antihistamines block that histamine to reduce the severity of your allergy symptoms. If your allergies are mild, you may not experience any symptoms from the medication.
The Types of Antihistamines
There are two main subtypes of antihistamines: H1 and H2 receptors. H1 receptors treat allergy symptoms and other conditions, such as sinus infections and bronchitis. Some healthcare providers use H1 receptors as a sleep aid. A few H1 receptors include:
- Hydroxyzine
- Azelastine
- Azelastine
- Cetirizine
- Desloratadine
- Fexofenadine
- Loratadine
- Brompheniramine
- Chlorpheniramine
- Clemastine
- Cyproheptadine
- Dimenhydrinate
- Diphenhydramine
- Doxylamine
H2 receptor antihistamines are used for gastrointestinal (GI) conditions like chronic acid reflux and peptic ulcer disease. Some H2 receptors include:
- Cimetidine
- Famotidine
- Nizatidine
Most over-the-counter antihistamines are sold under brand names like Allergra® or Claritin®.
Allergy-specific drugs will usually say antihistamine on the front of the package, but those used to treat other conditions, like GI disorders or insomnia, may not. In those cases, you can identify antihistamines by looking at the ingredients list, usually under the “active ingredient” section.
Where Can I Find Antihistamines?
Antihistamines are available through a prescription or sold over-the-counter at your local Frisco drugstore. Any allergy medication you bought from a drugstore likely contains antihistamines. They’re available as tablets, capsules, syrups, nasal sprays, eye drops and skin creams.
How Long Before an Allergy Test Can I Take Antihistamines?
Because skin allergy tests look for physical symptoms, you should avoid antihistamines for five to seven days before your test.
Can I Take Antihistamines Right After My Test?
You can take antihistamines as soon as your allergist reads the results.
If you have any more questions about taking antihistamines or other drugs before your allergy test, contact Collin County ENT.
[1] Cleveland Clinic. (n.d.). Histamine. https://my.clevelandclinic.org/health/articles/24854-histamine