A flare up in ulcerative colitis occurs when the inflammation in the lining of the colon or rectum becomes active after a period of remission. While the underlying cause of the disease is an overactive immune system, several external and internal factors can trigger this immune response to restart. Identifying these triggers is a vital part of managing the condition, as it allows patients to take proactive steps to maintain stability. In the United Kingdom, clinical management focuses on recognising these patterns early to adjust treatment before symptoms become severe. While some flare ups occur without an obvious cause, many are linked to specific environmental, physical, or lifestyle triggers.
What we will discuss in this article
- The impact of missing or changing medication on gut stability
- How psychological stress and emotional health influence the immune system
- The role of non steroidal anti inflammatory drugs in triggering flares
- How common infections and antibiotics can disrupt the gut microbiome
- Dietary factors and food sensitivities during active disease
- Seasonal changes and hormonal influences on inflammation
- Emergency guidance for severe or rapidly worsening symptoms
Medication non adherence
One of the most common and preventable causes of a flare up is missing doses of maintenance medication. Maintenance therapies, such as 5 ASAs or biologics, are designed to keep the immune system in check even when you feel perfectly well. Many patients mistakenly believe they can stop their treatment once they are in remission. However, without the medication to suppress the inflammatory response, the immune system often begins to attack the colon lining again. Even a few missed doses can sometimes be enough to allow inflammation to take hold. It is essential to discuss any changes to your medication with your gastroenterologist before taking action.
Stress and emotional well being
While stress does not cause ulcerative colitis, it is a well documented trigger for flare ups. The gut and the brain are connected through the gut brain axis, a network of nerves and chemical signals. Significant psychological stress, whether from work, personal life, or the anxiety of living with a chronic illness, can alter the gut environment and stimulate the immune system. During stressful periods, the body produces hormones like cortisol and adrenaline, which can increase gut sensitivity and potentially initiate an inflammatory cascade in the bowel.
Certain medications and painkillers
Not all over the counter medications are safe for individuals with ulcerative colitis.
Non-steroidal anti-inflammatory drugs
Common painkillers like ibuprofen, aspirin, and naproxen are known to irritate the lining of the gastrointestinal tract. In people with ulcerative colitis, these drugs can directly trigger a flare up or worsen existing inflammation. Healthcare professionals generally recommend using paracetamol instead for general pain relief, as it does not carry the same risk of intestinal irritation.
Antibiotics
Antibiotics are used to treat bacterial infections, but they also kill beneficial bacteria in the gut. This disruption of the gut microbiome can create an imbalance that triggers the immune system. Furthermore, antibiotic use increases the risk of developing a C. diff infection, which can mimic the symptoms of a severe colitis flare.
Infections and the gut microbiome
A simple stomach bug or a common cold can sometimes be enough to destabilise a person with ulcerative colitis. When the body is fighting a viral or bacterial infection, the immune system becomes highly active. In some cases, this generalised immune response can mistakenly refocus on the colon. Gastrointestinal infections, such as food poisoning, are particularly risky because they cause direct trauma to the gut lining, making it easier for a flare up to begin.
Dietary triggers
While diet is highly individual, certain foods can aggravate the gut during periods of increased sensitivity.
- High fibre foods: Raw vegetables and whole grains can be hard to process during the early stages of a flare.
- Dairy products: Some patients develop temporary lactose intolerance when their colon is inflamed.
- Spicy foods: Heat from chili can increase gut motility and cause pain.
- Artificial sweeteners: Compounds like sorbitol can draw water into the bowel and worsen diarrhoea.
Emergency guidance
Some flare ups can escalate into serious medical emergencies such as toxic megacolon or severe haemorrhage.
If you experience severe, sudden, or worsening symptoms, call 999 immediately.
Seek urgent medical assessment if you notice:
- Severe abdominal pain with a hard and visibly swollen tummy
- Passing large amounts of bright red blood or multiple large clots
- A high fever combined with severe shaking or chills
- Feeling very dizzy, faint, or having a rapid heartbeat
- More than six to ten bloody bowel movements in a twenty four hour period
To summarise
Flare ups in ulcerative colitis are often triggered by a combination of factors including medication non adherence, high levels of stress, and the use of certain medications like non-steroidal anti-inflammatory drugs. Infections and significant dietary changes can also disrupt gut stability. While it is not always possible to prevent every flare, understanding your personal triggers and maintaining a consistent medication schedule are the most effective ways to prolong periods of remission. Early recognition of a flare up allows for quicker medical intervention, which can prevent the inflammation from causing significant damage to the colon.
Can I take ibuprofen if I have a headache?
It is generally advised to avoid non-steroidal anti-inflammatory drugs like ibuprofen. Paracetamol is a safer alternative that does not typically trigger colitis flares.
Does stress always cause a flare?
No, but it is a major risk factor. Learning stress management techniques can be a helpful part of your overall management plan.
Will a single missed pill cause a flare?
One missed pill might not cause an immediate flare, but repeated missed doses significantly increase the risk over time.
Can I eat spicy food when I am in remission?
Many people can tolerate a wider variety of foods during remission, but it is important to reintroduce triggers slowly to see how your body reacts.
Are there seasonal triggers for colitis?
Some studies suggest that flares are more common in the spring and autumn, possibly due to changes in vitamin D levels or common seasonal viruses.
Can travel trigger a flare?
Travel can be stressful and often involves changes in diet and sleep, all of which can potentially trigger a flare. Planning ahead is key.
How soon should I call my doctor if I feel a flare starting?
You should contact your specialist nurse or doctor as soon as you notice a persistent change in your symptoms lasting more than two or three days.
Authority Snapshot
This article was reviewed by Dr. Stefan Petrov, a UK trained physician with an MBBS and postgraduate certifications including Basic Life Support, Advanced Cardiac Life Support, and the UK Medical Licensing Assessment. He has hands on experience in general medicine, surgery, anaesthesia, ophthalmology, and emergency care. Dr. Petrov has worked in both hospital wards and intensive care units, performing diagnostic and therapeutic procedures, and has contributed to medical education by creating patient focused health content and teaching clinical skills to junior doctors.
