If you’ve been dealing with unexplained stomach issues, rashes, or fatigue after meals, the source may be a hidden food allergy or intolerance. These reactions are more common than many realize, and they often go undiagnosed for years.
At Newtown Gastroenterology, our board-certified GI specialists provide clinically proven testing and personalized care to help uncover what’s really behind your symptoms. Whether you're reacting to dairy, gluten, or another common food trigger, we can help you find answers and take control of your health. Not sure if testing is right for you? Schedule a consultation and meet with one of our expert gastroenterologists in NYC.
Let’s explore the top food triggers and how we diagnose them.
Understanding the Difference Between Food Allergy and Food Intolerance
Many people experience discomfort after eating certain foods, but not all reactions mean you have a food allergy. While both food allergies and intolerances can cause symptoms like bloating, stomach pain, or rashes, the underlying causes and risks are very different.
- Food allergies involve the immune system and can be life-threatening.
- Food intolerances stem from digestive issues and are uncomfortable but not dangerous.
Accurate diagnosis is key. At Newtown Gastroenterology, our board-certified specialists provide advanced food allergy testing and intolerance evaluations using safe, evidence-based methods.
Top 10 Most Common Food Triggers
1. Dairy (Lactose & Milk Protein)
Dairy is one of the most common food-related issues. Some patients are allergic to casein or whey proteins in milk. Others are lactose intolerant due to a lack of lactase, the enzyme needed to digest lactose.
Symptoms may include:
- Hives, nasal congestion (allergy)
- Bloating, cramps, diarrhea (intolerance)
At Newtown Gastroenterology, we offer both skin prick allergy testing and hydrogen breath testing to diagnose milk protein allergy or lactose intolerance.
2. Gluten (Wheat)
Wheat allergy is an immune response, while gluten intolerance or non-celiac gluten sensitivity causes digestive symptoms without immune involvement. Celiac disease is another related autoimmune condition triggered by gluten.
Watch for:
- Hives or swelling (wheat allergy)
- Bloating, fatigue, or brain fog (gluten sensitivity)
We provide comprehensive GI evaluations to rule out celiac disease or gluten intolerance, along with dietary guidance to manage symptoms.
3. Peanuts and Tree Nuts
Nut allergies are among the most serious and often last a lifetime. Reactions can be immediate and severe, sometimes leading to anaphylaxis.
Common signs:
- Swelling of lips or throat
- Itching, rashes, or trouble breathing
Our team uses IgE blood testing or skin testing to confirm nut allergies and help you avoid life-threatening exposures.
4. Shellfish
Shellfish allergies affect both children and adults and can develop later in life.
Symptoms include:
- Vomiting or abdominal pain
- Difficulty breathing, hives
Due to the risk of severe reactions, proper food allergy testing near you is critical to avoid accidental exposure.
5. Eggs
Egg allergies are common in children but can persist into adulthood. People may react to the white, yolk, or both.
Possible symptoms:
- Skin rashes
- Stomach upset
- Nasal congestion
Our skin prick and IgE testing can determine sensitivity and guide egg-free nutrition planning.
6. Soy
Soy allergy is often seen in children and may be outgrown, though some individuals remain sensitive for life.
Typical symptoms:
- GI upset
- Hives
- Asthma-like symptoms
Soy is a common hidden ingredient. Our testing can help you manage dietary risks with confidence.
7. Fish
Fish allergies are distinct from shellfish allergies and often appear in adulthood. Reactions can occur even with airborne exposure during cooking.
Common reactions:
- Nausea
- Swelling
- Anaphylaxis in severe cases
Confirm with a targeted skin or blood test, especially if symptoms are unclear.
8. Fructose
Some individuals cannot properly absorb fructose, a sugar found in fruit, honey, and sweeteners. This leads to GI discomfort after eating otherwise healthy foods.
Symptoms:
- Bloating
- Gas
- Diarrhea
We use a hydrogen breath test at our New York City location to diagnose fructose intolerance and help patients make informed dietary choices.
9. Sucrose
Sucrose intolerance occurs when your body can’t break down table sugar. Like fructose intolerance, it can cause chronic digestive symptoms.
Signs to watch for:
- Abdominal pain
- Gas
- Loose stools
Testing is non-invasive and performed on-site by our GI specialists using the same hydrogen breath method.
10. Food Additives
Preservatives, colorings, and artificial sweeteners can cause food sensitivity reactions, especially in processed foods.
Reported symptoms:
- Headaches
- Skin flushing
- Digestive upset
Though not always detected by traditional allergy testing, we help patients identify additive sensitivities through structured elimination diets and monitoring.
Signs It’s Time to Get Tested for Food Allergies or Intolerances
You don’t have to keep guessing what's causing your symptoms or live with daily discomfort. If certain foods leave you feeling unwell, professional testing can provide clarity and relief.
Consider scheduling an evaluation if you experience:
- Bloating, gas, or abdominal pain after meals
- Ongoing diarrhea, constipation, or nausea
- Skin reactions like rashes, hives, or swelling after eating
- Fatigue, headaches, or brain fog following specific foods
- Persistent symptoms that don’t improve with elimination diets
At Newtown Gastroenterology, our board-certified gastroenterologists will review your health history and help you determine whether food allergy testing or intolerance evaluation is the right next step. Early diagnosis means faster relief and a plan you can trust.
How We Diagnose Food Reactions
At Newtown Gastroenterology, we offer clinically proven testing methods to accurately identify food allergies and intolerances. Our board-certified gastroenterologists use both immune-based and digestive function tests to pinpoint the source of your symptoms and help you find lasting relief.
Food Allergy Testing
We offer two main types of allergy testing:
- Skin Prick Test: This quick, minimally invasive test involves placing small amounts of allergens on your skin and lightly pricking the surface. If a raised bump or redness develops, it suggests an allergic response. Skin prick testing helps identify reactions to common allergens such as dairy, nuts, shellfish, and more.
- IgE Blood Test: This test measures your immune system’s response to specific foods by detecting Immunoglobulin E (IgE) antibodies. It’s especially useful for patients who cannot undergo skin testing due to eczema, sensitivity, or other medical concerns.
In selected cases, we may perform a supervised food challenge, where small amounts of a suspected allergen are consumed under medical observation to monitor for a reaction.
Food Intolerance Testing
We diagnose common food intolerances using:
- Hydrogen Breath Testing: This safe, non-invasive test measures hydrogen levels in your breath after consuming a sugar solution (lactose, fructose, or sucrose). A rise in hydrogen indicates poor digestion of that sugar, helping diagnose:
- Lactose intolerance
- Fructose intolerance
- Sucrose intolerance
All testing is conducted in our accredited clinical facilities using FDA-approved equipment and protocols. Our team ensures testing is both accurate and comfortable, providing a clear diagnosis so you can take confident steps toward symptom relief.
Why Patients Choose Newtown Gastroenterology
When searching for food allergy testing near me or a trusted gastroenterologist near me, patients across New York City turn to Newtown Gastroenterology for expert, compassionate care.
Here’s what sets us apart:
- Personalized Digestive Care: Every treatment plan is tailored to your unique symptoms, health history, and lifestyle.
- Advanced, Non-Invasive Testing: We offer accurate skin prick, blood, and breath tests to diagnose food allergies and intolerances.
- Experienced Specialists: Our board-certified gastroenterologists bring over 60 years of combined clinical expertise.
- Convenient NYC Locations: Multiple locations make it easy to access top-tier care close to home.
- Long-Term Support & Education: We’re committed to guiding you through every step, from diagnosis to symptom management and prevention.
Whether you're navigating persistent discomfort or simply seeking answers about your diet, our team is here to help you feel better, faster.
Feel Better, Eat Smarter: Let’s Find Your Triggers Together
Food allergies and intolerances can affect more than just your digestion; they impact energy, mood, and daily life. If you're tired of guessing or suffering through symptoms, Newtown Gastroenterology offers answers backed by experience and testing you can trust.
Schedule an appointment today with our board-certified team, and learn how our food allergy and intolerance testing can help you take back control of your health.
