With 2 clinics located in Central London and 2 in North-West London, Dr Arun Rajendran takes pride in offering expert, friendly, and effective care for a comprehensive range of conditions affecting the gullet, stomach, colon, and liver.
mailgastro@pm.me
London clinic and Onewelbeck
BMI The Clementine Churchill Hospital
OSD Healthcare
Dr Arun Rajendran provides specialist diagnosis and treatment for collagenous colitis at four private clinics across London — helping patients restore digestive balance and regain control.
Specialist gastroenterologist, London.
Accepted & Self-Pay.
Compassionate Specialist Care
Gastroenterology London
Collagenous colitis is a subtype of microscopic colitis — a chronic inflammatory condition of the colon.
The bowel appears normal on colonoscopy, but biopsies reveal a thickened collagen band beneath the intestinal lining, disrupting water absorption and causing persistent, watery diarrhoea.
Unlike Crohn's disease, it causes no visible damage, yet it significantly affects daily life.
It is most common in middle-aged women, though anyone can be affected.
Facts: Microscopic colitis — colon looks normal on the surface; Confirmed by biopsy, not visual examination alone; Most common in women aged 50–70; Not linked to increased bowel cancer risk; Highly treatable with specialist care.
The exact cause of collagenous colitis is not fully understood, but several key factors are recognised.
The immune system mistakenly attacks the colon lining, driving chronic inflammation and collagen build-up.
NSAIDs (e.g. ibuprofen) and proton pump inhibitors (e.g. omeprazole) are among the most common triggers.
A family history of autoimmune conditions or IBD may increase your risk.
Prior gut infections can disrupt the microbiome and trigger a lasting inflammatory response.
Chronic stress, poor diet, and smoking are linked to collagenous colitis flare-ups.
Coeliac disease, rheumatoid arthritis, and thyroid disorders are associated with higher risk.
Collagenous colitis symptoms often mimic IBS, making specialist assessment essential.
Chronic, watery diarrhoea (often 5–10 times daily), Abdominal pain and cramping, Bloating and excess wind, Urgent need to reach the toilet, Nocturnal diarrhoea.
Persistent fatigue and low energy, Unintentional weight loss, Dehydration, Nausea and reduced appetite, Brain fog and poor concentration.
If diarrhoea has persisted for more than four weeks or is disrupting your daily life, seek specialist assessment promptly.
You don't have to manage collagenous colitis alone. Expert, personalised care is available in London.
Because collagenous colitis shows no visible bowel damage, specialist investigation is essential for an accurate diagnosis.
Review of symptoms, medications, diet, and medical history to identify patterns and triggers.
Checking for inflammation markers, nutritional deficiencies, and ruling out infection.
The colon typically looks normal — but this step is essential to obtain accurate biopsy samples.
A thickened subepithelial collagen band of more than 10 micrometres confirms the diagnosis.
CT scan, breath tests, or coeliac screening may be arranged as needed.
Red-Flag Symptoms: Seek urgent specialist assessment if you notice blood in your stools, unexplained weight loss over 3 kg, diarrhoea persisting beyond six weeks, signs of severe dehydration, high fever with gut symptoms, or new symptoms appearing after age 60.
Dr Arun Rajendran tailors every treatment plan to the individual, based on the latest collagenous colitis treatment guidelines and his extensive clinical experience.
9 mg daily for 6–8 weeks to induce remission; Tapered to 3–6 mg daily for maintenance; Acts locally in the gut with minimal systemic side effects.
Loperamide — reduces urgency and frequency; Cholestyramine — helps where bile acid malabsorption is present; Oral rehydration therapy to replace fluids and electrolytes.
Thiopurines (e.g. azathioprine) — for ongoing disease; Biologics — for severe, steroid-dependent cases; Review and withdrawal of trigger medications.
Regular reviews to monitor treatment response; Clear, agreed plan for managing a collagenous colitis flare-up; Nutritional support and ongoing specialist guidance.
The right nutritional and lifestyle approach, combined with medical treatment, can significantly reduce flare-ups and improve quality of life.
Reduce gluten and lactose during active symptoms; Include anti-inflammatory foods (oily fish, turmeric, leafy greens); Limit caffeine, alcohol, and processed foods; Choose low-fibre, easily digestible options during a flare-up; Eat smaller, more frequent meals.
Manage stress with yoga, mindfulness, or breathing exercises; Stay well hydrated; Keep a symptom and food diary; Discuss all medications with your doctor.
Engage in gentle exercise; Follow a low-fat diet during symptomatic periods; Avoid smoking; Prioritise quality sleep.
Expert, friendly, and effective private gastro care — because you deserve more than a rushed appointment.
Thorough investigation before treatment, with a clear explanation in plain English.
Every plan is built around your specific diagnosis and lifestyle — not a generic protocol.
Continued follow-up, flare-up management, and access to a wider specialist network across London.
Conveniently located across central and south London, often available within days.
Thousands of patients across London and the UK have trusted
Dr. Arun Rajendran to get to the bottom of their digestive symptoms.
We are a self-pay clinic but also accept all major UK healthcare insurance providers.
Our London Clinic Locations
20 Devonshire Place, London, W1G 6BW (Wed: 17:45 – 19:30).
Welbeck Street, London, W1G 0AR (Mon: 18:00 – 20:00).
Sudbury Hill, Harrow, HA1 3RX
(Tue 18:00–20:00 · Alt Sat 08:30–10:30).
One Medical House, Hemel Hempstead, HP2 7YU
(Saturday: 09:00 – 11:00).