Solutions for Your Sulfa Allergy

Sulfa Allergy Symptoms, Testing & Treatment

Do you have a sulfa allergy? We can help. Dr. Sonia Cajigal is a board-certified allergist that can help you navigate sulfa allergy and other medication allergies. Learn more about sulfa allergy symptoms, testing, and treatment at St. Louis Family Allergy. Schedule your visit today! “Dr. Cajigal was friendly, professional, and informative. She took the time to explain the tests and what was going on with my allergies. She is so knowledgeable and really cared about how I was feeling. I would highly recommend this practice if you suffer from allergies and asthma.” – Sue D, July 2020
Sulfa Allergy Testing by Dr. Sonia Cajigal of St. Louis Family Allergy in St. Louis, Missouri
Drug Allergist Dr. Sonia Cajigal of St. Louis Family Allergy review badges and affiliations

About Sulfa Allergy

Medications with Sulfa
Sulfa Allergy Symptoms
Sulfa Allergy Testing
Sulfa Allergy Treatment
Sulfa (sulfonamides) is an ingredient found in many medications, including certain antibiotics, blood sugar medications, anti-inflammatory drugs, diuretics, and even some migration medications. Around 6% of people that are prescribed medications containing sulfonamides are found to have a sulfa allergy.
Drug Allergy Testing

in St. Louis, Missouri

Medications that cause sulfa allergy

What Medications Cause Sulfa Allergy?

Sulfa allergy reactions may be caused by oral medications (taken by mouth) or topical medications (applied to the skin).

Antibiotics that contain sulfa include:

  • Dapsone
  • Mafenide
  • Sulfacetamide
  • Sulfadiazine
  • Sulfadoxine
  • Sulfamethizole
  • Sulfanilamide
  • Sulfasalazine
  • Sulfisoxazole
  • Trimethoprim / Sulfamethoxazole (Trade names Bactrim and Sulfatrim)

Antibiotics with sulfonamides are commonly prescribed for burn infections, eye infections, urinary tract infections (UTIs), vaginitis, cystitis, inflammatory bowel disease (IBD), rheumatoid arthritis, crohn’s disease, ulcerative colitis, leprosy, dermatitis, pneumonia, and several other conditions bacterial infections.

Beyond antibiotics, other classes of drugs may contain sulfa. The following are some examples.

  • Certain blood sugar medications contain sulfa, including glyburide and glimepride.
  • Celecoxib (trade name Celebrex), a common nonsteroidal anti-inflammatory drug (NSAID), also includes sulfa.
  • Some diuretics contain sulfa.
  • Sumatriptan, a migraine medication, also contains sulfa.

Sulfa Allergy Symptoms

Sulfa allergy is most commonly recognized by skin rashes, hives, and sensitivity to sunlight after taking a medication containing sulfonamides, though you may experience additional symptoms. More severe symptoms are also possible, such as swelling in the throat or shortness of breath.

Common Sulfa Allergy Symptoms

  • Itchy skin
  • Rash
  • Hives
  • Sensitivity to sunlight (rash worsens when exposed to sun)
  • Swelling in the hands, feet, mouth, tongue
  • Nause, vomiting or diarrhea
  • Headache
  • Less Common Sulfa Allergy Symptoms:

    • Difficulty swallowing
    • Difficulty breathing
    • Muscle and joint aches
    • Sore throat
    • Fever and flu-like symptoms
    • Skin blisters and peeling skin

    Severe Sulfa Allergy Symptoms (Rare):

    • Anaphylaxis (life threatening allergic reaction)
    • Stevens-Johnson syndrome
    • Toxic epidermal necrolysis (TEN)
    Stevens-Johnson syndrome and toxic epidermal necrolysis (TEN) are conditions that cause your skin, mouth or genitals to develop rashes and blisters, and then peel. Seek immediate medical attention if you experience anaphylaxis, Stevens-Johnson syndrome, or TEN.
    Drug Allergy Testing

    in St. Louis, Missouri

    Sulfa allergy symptoms

    Sulfa Allergy Testing

    When a patient has an adverse response to a medication, they often come to believe that they have a drug allergy, and may even be told by their doctor that they have an allergy, even without formal allergy testing. Unnecessarily avoiding medications can complicate medical treatment and may lead to worse outcomes, which is why individuals with suspected drug allergies should seek formal testing. Unfortunately, there are very few options to test for sulfa allergy. In fact, many common resources state that there are no diagnostic tests for sulfa allergy. However, a recent study at Vanderbilt has shown that an oral drug challenge can disprove sulfa allergy in low-risk cases, when allergic reactions have been only mild or moderate. An oral drug challenge is when you take a medication under the supervision of an allergist.

    Sulfa Allergy Treatment

    It’s impossible to know if you have a sulfa allergy prior to your first reaction. If you experience any of the symptoms described above, contact the doctor that prescribed your medication immediately to see if there’s an alternative medication that you can start to take. For immediate allergy symptom relief, antihistamines and/or corticosteroids may help. Avoiding medications with sulfonamides is key to preventing future reactions:
    • Communicate with your healthcare providers. Make your allergy known to every healthcare provider that you visit so that they can avoid medications with sulfonamides and prescribe alternatives.
    • Carry a medical alert card or wear a medical alert bracelet that alerts care staff of your sulfa allergy.
    • Be sure to read the ingredients lists on medications before you take them.
    If you must take a medication containing sulfa, desensitization may be an option. Desensitization consists of taking more and more of a medication that you’re allergic to until you can safely tolerate a full dose. Desensitization may help you get through a course of medication, but it will not cure your sulfa allergy.


    [1] American College of Allergy, Asthma & Immunology: [2] Asthma and Allergy Foundation of America:
    More Specialties


    Drug Allergies

    Eye Allergies

    Food Allergies

    Nasal Allergies

    Skin Allergies

    Allergy Shots

    Allergy Testing

    Biologic Therapy

    St. Louis Family Allergy logo
    Visit Allergist Dr. Sonia Cajigal of St. Louis Family Allergy in St. Louis, Missouri

    Drug Allergy Specialist
    Dr. Sonia Cajigal

    Schedule Your Visit

    St. Louis Family Allergy Google review score badge
    "Dr. Cajigal was friendly, professional, and informative. She took the time to explain the tests and what was going on with my allergies. She is so knowledgeable and really cared about how I was feeling. I would highly recommend this practice if you suffer from allergies and asthma."

    - Sue D, July 2020

    “Dr Cajigal is a great listener. She trusts her patients instead of treating them as if they are not the experts of their own bodies. I really appreciate that (many doctors do not have that quality). She also immediately treats the symptoms instead of waiting to see if things clear. I use her for my children and myself. We have never left her office feeling as if it was a waste of time.”

    – Stephanie, August 2020

    "Great Allergist!"

    - Ann H, December 2018

    "She is the best."

    - Stephen W, June 2020

    Schedule Your Visit

    We are currently accepting new adult and pediatric patients at St. Louis Family Allergy!

    Reach out by phone, instant message, email, or the submission form below to schedule your visit.

    Call St. Louis Family Allergy icon

    (314) 530-6080

    Call us anytime
    M-Th, 8:30am-4pm

    Message St. Louis Family Allergy icon

    Instant Messaging
    Use Our Chat Window

    We typically respond
    within 3 to 5 minutes

    Email St. Louis Family Allergy icon


    Email us or use this
    contact form

    You can also use this contact form for general inquiries.