Potential triggers of Crohn’s disease flares can vary from person to person. Some common triggers may include stress, certain medications, dietary choices, smoking, and infections.

Crohn’s disease is a type of inflammatory bowel disease (IBD) that can negatively affect a person’s quality of life. The condition is chronic and involves periods of remission and flares.

Flares — periods when symptoms worsen — can result from internal or external triggers. Triggers can vary from person to person, and identifying a person’s triggers is an important aspect of treating and managing Crohn’s disease.

Once a person knows their triggers, they can take steps to avoid them and to manage their symptoms when a flare occurs.

This article reviews several common triggers for Crohn’s disease flares, ways to manage symptoms, and when to speak with a doctor.

A trigger is anything a person comes in contact with, internally or externally, that causes their Crohn’s symptoms to flare. Though triggers can vary between people, the following are some common triggers.

1. Stress

Stress plays an important role in overall health. Managing stress can have several benefits for a person, including potentially helping prevent flares of Crohn’s symptoms.

According to a 2020 review of studies, a chronically high perceived stress level has an independent association with relapse (flares) of symptoms.

The relationship between stress and symptoms is bidirectional. This means that when symptoms worsen, a person’s perceived stress tends to increase, which could possibly worsen symptoms.

Once their symptoms are manageable, a person is less likely to report stress related to IBD.

2. Medications

Certain medications, such as the following, can increase the risk of worsening or triggering Crohn’s disease symptoms:

  • nonsteroidal anti-inflammatory drugs, including aspirin, ibuprofen, and naproxen
  • certain antibiotics
  • oral contraceptives
  • some vaccines

A person should tell their doctor if they notice increasing symptoms or greater symptom severity after taking a medication. They may also want to discuss which medications they can safely take for headaches, illness, or other situations in which they may want to use over-the-counter (OTC) or prescription medications.

A doctor can advise a person on what medications may be safe and less likely to trigger a flare.

3. Incorrect use of medications

A doctor will likely prescribe different medications to help manage Crohn’s disease.

A person will need to continue taking their medications as prescribed to help prevent a flare. Missing doses or taking the medication incorrectly can lead to a flare.

4. Diet

The foods a person eats can affect their Crohn’s symptoms. In fact, diet plays an important role in managing Crohn’s disease.

As with other treatments, no one option works for everyone. A person will need to experiment with different foods to see which ones work best for them.

According to the Crohn’s and Colitis Foundation, common food triggers include:

  • high fiber foods such as asparagus, Brussels sprouts, cabbage, and cauliflower
  • foods high in insoluble fiber (which does not dissolve in water), such as raw kale, apple skin, and sunflower seeds
  • high lactose foods such as cow’s milk, cream, ice cream, and custard
  • sugar alcohols and artificial sweeteners, including sorbitol, mannitol, xylitol, sucralose, aspartame, and saccharin
  • high fat foods such as butter, cheesy dishes, and fried foods
  • added sugars and sugary foods, including cookies, pastries, coconut sugar, honey, and maple syrup
  • alcohol
  • spicy foods such as sriracha, chili powder, and hot sauce
  • sugar-sweetened beverages
  • caffeinated coffee, tea, energy drinks, and other caffeinated beverages

Foods that do not appear on this list may also trigger symptoms. A person can consider recording the foods they eat and the symptoms they experience. If symptoms worsen after eating a certain food, they can try removing that food from their diet.

5. Smoking

Smoking is a known risk factor for Crohn’s disease.

In a 2022 study, researchers noted that smoking had a negative effect on Crohn’s disease severity. They found that smoking had an association with higher rates of stricturing and penetrating disease and increased likelihood of needing surgery for the condition.

“Stricturing” refers to a narrowing of the intestines, and “penetrating disease” means that there is evidence of an abscess or fistula in any location.

People with Crohn’s disease should consider taking steps to quit smoking, if applicable, and to avoid secondhand smoke exposure.

6. Infections

Infections, particularly of the gastrointestinal tract, can cause Crohn’s disease symptoms to flare.

For example, a Clostridium difficile (C. difficile) infection can cause IBD symptoms to worsen. C. difficile causes diarrhea and inflammation in the colon.

If a person has both Crohn’s disease and a C. difficile infection, they will need to treat both conditions before their symptoms will improve. A doctor may check for this bacterium in a person’s stool when there is evidence of a possible flare.

Viral infections can also trigger an immune response, which can worsen IBD symptoms.

Additionally, Crohn’s disease can increase a person’s chances of contracting common illnesses. Both IBD itself and the medications a person may take to treat it, such as steroids, contribute to the increased risk.

7. Environmental factors

Environmental triggers are a broad category and can include anything a person comes in contact with that sets off Crohn’s disease symptoms.

Possible environmental triggers include:

  • air pollution
  • water pollution
  • changes to the gut microbiome
  • low vitamin D levels
  • sleep
  • breastfeeding
  • surgery

Like other triggers, environmental triggers can vary between people. Keeping a list of possible triggers could help a person identify and avoid them.

A person should consult a doctor as soon as possible if they experience a flare. A doctor can help a person manage symptoms and get the disease back into remission.

When a flare occurs, a person can take the following steps to help ease their symptoms at home:

  • using a moist towelette to wipe after using the toilet
  • applying skin protectant to the anus
  • using a warm salt bath to soothe anal fissures
  • using OTC pain medications such as acetaminophen
  • resting and getting as much sleep as possible

The best way to manage Crohn’s disease is to help prevent flares. Steps that may help include:

  • attending regular medical appointments
  • following doctors’ advice on regular procedures and testing
  • tracking Crohn’s disease symptoms between appointments
  • exercising regularly
  • quitting smoking, if applicable
  • finding healthy ways to manage stress
  • avoiding known triggers

Experts recommend consulting a doctor as soon as possible if a flare occurs. A doctor can help determine whether inflammation or another underlying cause is responsible for the flare. This can affect how they treat the symptoms.

A flare is a possible sign that the disease is no longer under control. A doctor may recommend changes to medications and treatment methods to help bring the disease into remission.

Crohn’s disease involves periods of remission and flares. Triggers can cause a person’s symptoms to flare and worsen for a period of time.

Triggers can vary between people. Common triggers include certain foods, smoking, stress, illness, some medications, and other environmental factors. A person should record possible triggers and try to avoid them.

If a flare occurs, a person should consult a doctor as soon as possible. A doctor can help determine the cause, treat the symptoms, and prevent additional flares.