Allergy Testing and Food Intolerance: Private Assessment in London
Allergies in the UK are rising rapidly. Roughly 44% of British adults now suffer from at least one allergy, and hospital admissions for severe allergic reactions have increased by 615% over the past 20 years. Food allergies affect approximately 2% of adults and 7-8% of children, while food intolerances — which produce uncomfortable but non-dangerous symptoms — are even more common.
Yet the NHS pathway for allergy investigation is notoriously slow and limited. Routine NHS allergy referrals can take months, and many GP practices have limited access to comprehensive allergy blood panels. If you suspect a food allergy or intolerance, waiting months for answers is both frustrating and potentially dangerous.
The Online GP by The Wellness provides same-day allergy and intolerance assessments, with blood test results typically within 24-48 hours. Allergy blood panels from £99. Comprehensive gut health investigations available.
Think you have a food allergy or intolerance? WhatsApp us now to arrange testing. Or email team@thewellnesslondon.com.
Understanding Food Allergy vs Food Intolerance
These terms are often used interchangeably, but they are fundamentally different conditions requiring different approaches.
Food allergy (IgE-mediated). Your immune system mistakenly identifies a food protein as a threat and produces IgE antibodies against it. On subsequent exposure, these antibodies trigger an immune response that can range from mild (hives, itching, mouth tingling) to severe (throat swelling, breathing difficulty, anaphylaxis). Reactions typically occur within minutes to two hours of eating the trigger food. Common food allergens include peanuts, tree nuts, shellfish, fish, cow's milk, eggs, wheat, and soya.
Food allergies can be life-threatening. If you or your child have experienced a severe allergic reaction, immediate medical assessment is essential, and you should carry an adrenaline auto-injector (EpiPen).
Food intolerance (non-IgE). Your body has difficulty digesting certain foods, but the immune system is not involved in the same way. Symptoms are typically digestive — bloating, abdominal pain, diarrhoea, nausea, wind — and develop more gradually, often hours or even days after eating the trigger food. Common intolerances include lactose intolerance (inability to digest milk sugar), fructose malabsorption, histamine intolerance, and sensitivity to FODMAPs (a group of fermentable carbohydrates).
Food intolerances are uncomfortable and can significantly affect quality of life, but they are not immediately dangerous in the way allergies can be.
What We Test
IgE Allergy Blood Testing
Specific IgE blood tests measure the antibodies your immune system produces against individual allergens. We offer panels for common food allergens (nuts, shellfish, dairy, eggs, wheat, soya, fish, sesame), environmental allergens (house dust mite, grass pollen, tree pollen, cat dander, dog dander, mould), and individual allergen testing when specific triggers are suspected.
Blood testing is safe, reliable, and does not carry the risk of triggering an allergic reaction (unlike skin prick testing, which should be performed in specialist settings).
Coeliac Disease Screening
Coeliac disease is an autoimmune condition triggered by gluten (found in wheat, barley, and rye) that damages the lining of the small intestine. It affects approximately 1 in 100 people in the UK, but only around 30% are diagnosed — meaning roughly 500,000 people are living with undiagnosed coeliac disease.
Symptoms include bloating, diarrhoea, abdominal pain, fatigue, anaemia, weight loss, mouth ulcers, and a specific itchy skin rash (dermatitis herpetiformis). Some people have no digestive symptoms at all and present only with anaemia or fatigue.
Screening involves a tTG-IgA blood test. You must be eating gluten regularly (at least one meal containing gluten daily for 6 weeks) before testing for accurate results. If the blood test is positive, a small bowel biopsy confirms the diagnosis.
Lactose Intolerance Assessment
Lactose intolerance — the inability to digest the sugar in dairy products — is extremely common globally, affecting an estimated 68% of the world's population and approximately 5-15% of Northern Europeans. Our doctors can arrange hydrogen breath testing or trial dietary elimination with clinical guidance.
A Warning About Commercial Intolerance Tests
The high street and internet are flooded with commercial food intolerance tests costing £50-300+ that claim to identify problematic foods through IgG antibody testing, hair analysis, or muscle testing (kinesiology). These tests are not supported by scientific evidence.
IgG antibodies to food are a normal part of the immune response — their presence simply indicates that you have been exposed to a food, not that you are intolerant to it. The British Society for Allergy and Clinical Immunology, the European Academy of Allergology, and NICE do not recommend IgG testing for food intolerance diagnosis.
If you have spent money on these tests and received a long list of "intolerances," we strongly recommend a proper medical assessment before eliminating multiple food groups from your diet, as unnecessary dietary restriction can itself cause nutritional deficiencies.
Get proper medical allergy testing, not guesswork. WhatsApp us to arrange evidence-based testing.
Gut Health and Digestive Investigation
If you are experiencing persistent bloating, abdominal pain, changes in bowel habits, or digestive discomfort, the cause may extend beyond simple food intolerance. Our doctors can investigate conditions including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), small intestinal bacterial overgrowth (SIBO), Helicobacter pylori infection (a common cause of stomach ulcers), bile acid malabsorption, and pancreatic insufficiency.
Investigation may include blood tests, stool tests (calprotectin to distinguish IBS from IBD, H. pylori testing), and referral for breath testing or endoscopy where indicated. Early investigation and accurate diagnosis save months of dietary experimentation and unnecessary restriction.
📧 Email team@thewellnesslondon.com
📞 Call 020 3951 3429
📍 10 Portman Square, Marylebone, London W1H 6AZ
This article was written by the medical team at The Online GP by The Wellness. Last updated: February 2026. If you are experiencing a severe allergic reaction (difficulty breathing, throat swelling, widespread hives, feeling faint), call 999 immediately and use your adrenaline auto-injector if you have one.
