Introduction
Diarrhoea means loose or watery stools occurring more frequently than normal, and it's one of the most common reasons people seek medical care. The single most useful distinction in evaluating diarrhoea is duration: acute diarrhoea, lasting under two weeks, is usually infectious and self-limited. Chronic diarrhoea, lasting more than four weeks, points toward a different, more specific set of causes and needs proper investigation rather than ongoing symptomatic treatment. At KAGE, that distinction — and the specific cause behind chronic cases — is what actually drives the diagnostic approach.
Acute diarrhoea: causes and management
Acute diarrhoea is most often caused by an infection — viral, bacterial, or parasitic — typically from contaminated food or water. Most cases resolve on their own within a few days. Rehydration, primarily with oral rehydration solution, is the most important part of treatment for the large majority of cases; antibiotics are not automatically needed and are reserved for specific situations, such as certain bacterial infections or more severe presentations, since they aren't effective against viral causes and aren't always appropriate even for bacterial ones.
Chronic diarrhoea in India: a different diagnostic picture than the West
Chronic diarrhoea — lasting more than four weeks — needs proper investigation rather than continued symptomatic treatment, and the likely causes differ meaningfully in India compared to Western textbooks. A hospital-based study of chronic small-bowel diarrhoea in Western India found intestinal tuberculosis and celiac disease tied as the two most common identifiable causes, each accounting for roughly a quarter of cases, with tropical sprue now a comparatively rare cause following improvements in sanitation. This matters practically because intestinal tuberculosis is a well-recognized mimic of Crohn's disease — the two can look strikingly similar on colonoscopy and even on biopsy in some cases — yet their treatments are entirely different: anti-tuberculosis therapy for one, immune-modulating therapy for the other. Getting this distinction wrong in either direction carries real consequences, which is why chronic diarrhoea in this region is evaluated with that possibility specifically in mind, not assumed to be IBD by default.
Telling intestinal TB and Crohn's disease apart: clinical clues
No single feature is definitive, but certain patterns help distinguish the two, based on comparative Indian clinical data:
| Feature | More typical of Crohn's disease | More typical of intestinal TB |
|---|---|---|
| Duration of symptoms before diagnosis | Longer (often years) | Shorter (often months) |
| Rectal bleeding | More common | Less common |
| Fever | Less common | More common |
| Ascites (fluid in the abdomen) | Less common | More common |
Because overlap exists and the stakes of misdiagnosis are high, biopsy, specific TB testing, and sometimes a period of close monitoring are used together rather than relying on any single clinical feature alone.
Other important causes of chronic diarrhoea
- Celiac disease — see the dedicated Celiac Disease page; a leading cause of chronic small-bowel diarrhoea in Indian data
- Inflammatory bowel disease (Crohn's disease and ulcerative colitis)
- IBS-D — diarrhoea-predominant irritable bowel syndrome
- Chronic parasitic infection, including amoebiasis, which can also cause bloody diarrhoea in its more severe form
- Lactose intolerance or other food-related intolerances
- Certain medications
- Malabsorption from other underlying conditions
Symptoms of diarrhoea
- Loose or watery stools, more frequent than usual
- Abdominal cramping
- Urgency
- In chronic cases: weight loss, fatigue, and signs of nutrient deficiency can develop over time
- Blood or mucus in the stool — always worth prompt evaluation, not assumed to be a routine infection
How diarrhoea is diagnosed
- For acute cases: often clinical assessment alone; stool testing when severe, bloody, persistent, or in specific risk situations
- Stool studies — culture, ova and parasite examination, and specific toxin testing where indicated
- Blood tests — to assess for anemia, inflammation, and nutritional deficiencies in chronic cases
- Colonoscopy with biopsy — essential for chronic diarrhoea, both to identify inflammatory bowel disease and to specifically look for and rule out intestinal tuberculosis
- Celiac disease testing, given how common it is as a cause of chronic diarrhoea in this setting
Diarrhoea treatment: matched to cause and duration
- For most acute diarrhoea: oral rehydration solution, continued (not withheld) nutrition, and time — most cases resolve without specific treatment
- Targeted antibiotics only when a specific bacterial cause is identified or strongly suspected, and clinically appropriate — not as a default response to any diarrhoea
- Antiparasitic treatment for confirmed parasitic infections such as amoebiasis
- Full anti-tuberculosis therapy (typically 6–9 months) for confirmed intestinal tuberculosis
- Condition-specific treatment for chronic causes once identified — a gluten-free diet for celiac disease, immune-modulating therapy for inflammatory bowel disease, or dietary and targeted medication for IBS-D
Diarrhoea care at KAGE
Short-lived diarrhoea is usually acute gastroenteritis and settles on its own. Diarrhoea that lasts beyond four weeks, wakes you at night, or comes with blood or weight loss is investigated properly by our gastroenterologists, and inflammatory causes are then managed through the IBD Clinic; children with the same picture are assessed for pediatric IBD. If diarrhoea has become chronic rather than an isolated episode, book a consultation.
Frequently asked questions
Not necessarily. In India, leading causes of chronic diarrhoea include intestinal tuberculosis, celiac disease, and inflammatory bowel disease alongside infectious causes — which is why proper testing matters rather than assuming an infection by default.
The two can look very similar, even on colonoscopy. Differences in symptom duration, fever, rectal bleeding, and specific biopsy and TB testing together help distinguish them — no single sign is definitive on its own, which is why thorough evaluation matters given how different the treatments are.
Not usually. Most acute diarrhoea is viral or self-limiting and improves with rehydration alone. Antibiotics are reserved for specific bacterial causes or more severe presentations, based on assessment or stool testing.
Rehydration, primarily with oral rehydration solution, is the most important part of treatment for the vast majority of cases — more important than any specific medication.
Consultation and standard diagnostic testing are generally covered under most health insurance plans; our team can help verify your specific coverage during consultation.
Signs of severe dehydration, bloody diarrhoea with high fever, or signs of sepsis need immediate medical attention — especially in young children, older adults, or anyone immunocompromised.
Yes — chronic diarrhoea is a common presentation of celiac disease, which is a leading identifiable cause of chronic small-bowel diarrhoea in Indian data. See the Celiac Disease page for more detail.
With a full course of anti-tuberculosis therapy, typically lasting 6–9 months. Completing the entire course, even after symptoms improve, is essential to avoid treatment failure and drug resistance.
Yes, and it can also cause bloody diarrhoea and, in more severe cases, complications like colitis. It's identified through stool testing and treated with specific antiparasitic medication.
The underlying causes and evaluation approach can differ in children. KAGE's pediatric gastroenterology team manages diarrhoea evaluation in children.
Book a consultation at KAGE
Speak to a KAGE gastroenterologist about your symptoms, your diagnosis, or a second opinion.