Food Allergy Program

The allergists at Tufts Medical Center provide integrative, patient-oriented, multidisciplinary and evidence-based care for both adults with known or suspected food allergies or food hypersensitivity causing gastrointestinal disorders and other conditions.

We provide care for a number of food allergies in children and related diseases including:

  • IgE mediated food allergies (e.g. peanut allergy, cow milk allergy and etc)
  • Eosinophilic esophagitis
  • Food protein-induced proctitis/colitis and enteropathy of infancy
  • Food protein-induced enterocolitis syndrome (FPIES)
  • Celiac disease
  • Non-celiac gluten hypersensitivity
  • Oral allergy syndrome
  • Food-dependent exercise-induced anaphylaxis
  • Lactose and fructose intolerance
  • Abdominal pain associated with food ingestion
  • Food aversion/phobia
  • Allergic contact dermatitis

Patients with food allergy and/or food associated gut disorders suffer from a wide spectrum of symptoms ranging from swallowing difficulty to life-threatening anaphylaxis. In the Division of Allergy at Tufts Medical Center, our board-certified allergists provide the full range of diagnosis and care needed for this range of allergies. 

Given the diagnostic challenge of these complex disorders, we believe clinical history is the most important component of the evaluation. We will assist new patients to obtain outside medical records, and our physician will carefully review these documents prior to your visit. Recommendations will be made for specific diagnostic tests to confirm the diagnosis and to formulate therapy only after a careful review of your clinical history, physical examination and previous laboratory, histological and endoscopic data.

We offer the most comprehensive state-of-art studies at our center, including specialized Allergy studies such as supervised oral food challenge, skin prick testing, patch testing and component-resolved diagnostics. Specialized genetic and metabolic studies also are available in selected cases.

If you are being evaluated food allergy, we would like to minimize the number of visits that you need for a diagnosis to be made.  The following measures will expedite your evaluation:

  • Any skin testing will require that you NOT take the following medication for 7 days prior to your visit:
    • Diphenhydramine (Benadryl)
    • Chlorpheniramine (Chlor-Trimeton)
    • Brompheniramine (Dimetapp)
    • Clemastine (Tavist, Antihist)
    • Cyproheptadine (Periactin)
    • Doxepin (Adapin, Silenor, Sinequan)
    • Combination Drugs (Actifed, Drixoral, Trinalin)
    • Loratadine (Claritin)
    • Fexofenadine (Allegra)
    • Cetirizine (Zyrtec)
    • Hydroxyzine (Vistaril, Atarax)
    • Azelastine nasal spray (Astelin, Asteopro)
    • Olopatadine nasal spray (Patanase)
    • Some over the counter sleep aids
  • Previous medical records are always helpful if you have been referred from outside of Tufts Medical Center (this might include Hospital discharge summaries, Physician Office Records, X-ray reports)
    • At your initial visit expect to spend two hours with us.  We will conduct:
    • An interview regarding your medical history
    • An environmental, occupational, social and family history
    • A physical examination
    • If medically indicated: skin testing, lung function testing and laboratory tests.
    • Special procedures such as drug challenges and some drug testing and certain desensitization treatments will generally be scheduled for a future visit.

A hydrogen breath test provides information about the digestion of certain sugars or carbohydrates, such as milk sugar (lactose) and fruit sugar (fructose). The test is also used for detecting abnormal growth of bacteria within the small bowel. Bacterial overgrowth can cause a variety of symptoms including bloating, diarrhea, burping and abdominal cramps. The test takes ~3 hours.

Preparation for the test

For four weeks before your test, you should not take any antibiotics.

For one week before your test, avoid any laxatives and stool softeners (for example Colace®, Milk of Magnesia®, Ex-Lax®) or stool bulking agents (for example Metamucil® or Citrucel®). You should also not undergo any test that requires cleansing of the bowel, such as colonoscopy or barium enema.

The day before your test:

  • You may consume only the following foods and drinks: plain white bread, plain white rice, plain white potatoes, baked or broiled chicken or fish, water, and non-flavored black coffee or tea.
  • Only salt may be used to flavor your food. Butter and margarine are not permitted.
  • Soda/cola drinks are not permitted.
  • Do not eat or drink anything else – it could give false results for the test.
  • Specifically, avoid beans, pasta, fiber cereals, and high fiber foods.
  • The night before the test, have an early dinner of rice and meat.

For 12 hours before your test:

  • You must stop eating and drinking 12 hours before the test. For example, if your test is at 8:00 am, you would stop eating and drinking at 8:00 pm the night before.
  • You may continue to take your usual prescribed medicines with water until 12 hours before the test.
  • Please bring all prescription medications to your appointment.

The day of your test:

  • You should not eat or drink anything in the morning.
  • You may take your medications with a small amount of water. If you are diabetic requiring insulin or diabetic pills, ask your physician if you should change your morning dose. Generally, half of your normal long-acting insulin is given. Oral hypoglycemic medications are usually not taken that morning until completion of the test and resumption of eating meals.
  • Brush your teeth 2 hours before the test.
  • Do not eat, drink, chew gum or tobacco, smoke cigarettes, or eat breath mints or candy before or during the test

Download PDF document.


Download a PDF version of the Hydrogen Breath Test Instructions


Download PDF document.


Download a Chinese language PDF of the Hydrogen Breath Test Instructions


Download Word document.


Download a Spanish language document of the Hydrogen Breath Test Instructions

Please bring the food that you or your child will be challenged with and your auto-injectable epinephrine (Epi-Pen/auvi-Q) to the appointment.

If you have questions, please call our office.

7 Days Before Challenge:

Stop any oral antihistamine medications. This includes Benadryl (diphenhydramine), Zyrtec (cetirizine), Claritin (loratidine), Allegra (fexofenadine), and Atarax (hydroxyzine).  There are many other antihistamines, so it is important to read all medication labels carefully, especially over-the-counter allergy/sinus/cold medications. If you have any questions, or if you take any of these medications within 1 week of the challenge, please contact our clinic.

If you have asthma, please continue your daily inhaled steroid medications for asthma (Flovent, Advair, Pulmicort, Symbicort, Asmanex) and/or Singulair.

If you use albuterol, Xopenex or any bronchodilator medication more than two times (except prior to exercise) in the week before the food challenge, please contact our clinic.

You can continue inhaled steroid nasal sprays (Flonase, Nasonex, Rhinocort), but please

Stop antihistamine nasal sprays (Astelin, Astepro).

Day of the Challenge:

You can have only clear liquids (e.g., water, fruit juices that have no pulp, sports drinks, popsicles) for 2 hours prior to the challenge.

Please arrive on time.

During the challenge, vital signs, oxygen saturation, breath sounds, and skin assessments will be performed regularly.  We will also ask you to note any signs or symptoms that you observe and report them immediately to us. 

You will be in the clinic for several hours. Please bring something to occupy yourself such as a laptop, book, ipad, etc.

During the challenge, no other food should be ingested.

Following the food challenge, you will be given specific recommendations depending upon the outcome of the challenge.

Please do not hesitate to call our clinic for any questions or concerns: 617-636-0136 (pediatrics) and 617-636-5333 (adults)

Download PDF document.


Download a PDF version of the Food Challenge Preparation Instructions


Download PDF document.


Download a Chinese language PDF of the Food Challenge Preparation Instructions


Download Word document.


Download a Spanish language document of the Food Challenge Preparation Instructions

John L. Ohman, Jr., MD

John L. Ohman, Jr., MD

Accepting New Patients

Virtual Appointments Available

Title(s): Chief, Division of Allergy; Professor, Tufts University School of Medicine
Department(s): Medicine, Rheumatology, Allergy and Immunology
Appt. Phone: 617-636-5333
Fax #: 617-636-4843

Asthma, hay fever, chronic sinusitis, food allergy, adverse drug reactions, insect sting allergy, occupational allergy/ respiratory disease, atopic eczema, hives/urticaria, adult immunodeficiency, skin testing, pulmonary function testing, allergen challenge

View Full Profile for John L. Ohman, Jr., MD


Food Allergy Clinic
Tufts Medical Center
800 Washington Street
Boston, MA 02111


Phone: 617-636-5333
Fax: 637-636-4843