Fever is a possible symptom of Crohn’s disease, as well as its complications. It’s also a possible side effect of certain Crohn’s disease medications.

Crohn’s disease is a type of inflammatory bowel disease (IBD) that causes chronic inflammation in your digestive tract. It’s known for causing gastrointestinal (GI) symptoms like diarrhea and abdominal cramps, which can progress over time as the inflammation worsens.

When left untreated, Crohn’s disease can progress to more systemic inflammation, as well as ulcers, intestinal obstruction, and other GI effects.

While Crohn’s primarily affects your small intestine and the upper portion of your large intestine (colon), it can also cause symptoms that may not seem GI-related. This includes fever.

If you have Crohn’s disease, it’s important to alert a doctor about a fever so they can determine whether the fever is a symptom of your condition, a possible sign of complications, or a side effect of medications you’re taking.

The exact symptoms of Crohn’s disease can vary. However, some of the most common symptoms include diarrhea, constipation, and abdominal pain.

A fever can be nonspecific, but if you have Crohn’s disease and are experiencing a high temperature, it’s possible that your fever might be related to this condition.

A low grade fever is more commonly due to Crohn’s underlying inflammation, while a high grade fever is more typical for overlapping infection made worse by Crohn’s.

As a symptom

Crohn’s disease is a progressive condition that’s also known for having periods of flare-ups and remission. As it progresses, it can cause symptoms beyond your intestines. Fever is one possible symptom of systemic inflammation Crohn’s disease causes.

In fact, some people experience fever and general unwellness as early symptoms of Crohn’s. Since fever can be related to numerous other conditions, though, you might not suspect a high temperature is related to Crohn’s disease unless you experience GI symptoms, too.

Aside from Crohn’s, other examples of noninfectious, inflammatory causes of recurring fever include lupus, rheumatic fever, and sarcoidosis.

As a complication

Along with fever, signs that Crohn’s disease inflammation is affecting other parts of the body may include the following symptoms:

  • night sweats
  • fatigue
  • appetite loss
  • unintentional weight loss
  • mouth ulcers
  • skin rashes
  • joint pain and swelling
  • eye pain and swelling

It’s also possible for Crohn’s disease to cause an infection. In such cases, you may need antibiotics. Antibiotic treatment can help treat the underlying infection and also alleviate related symptoms like fever.

Crohn’s disease can cause other complications, such as:

If you have Crohn’s disease, a doctor may prescribe medications to help reduce inflammation and stop your immune system from attacking your intestines. These include steroids, immunosuppressants, and biologics.

Both steroids and immunosuppressants can weaken your immune system and make you more prone to infections. If you do develop an infection, a fever is one possible symptom.

Some people with Crohn’s disease take biologics to help manage their condition. These are typically prescribed when other treatments don’t work.

In most cases, biologics are taken for the rest of your life, unless they stop being effective. This is because stopping use may lead to your building a resistance to the drug. Biologics may also cause side effects.

Symptoms of a reaction to biologics include:

  • high fever
  • joint or muscle aches
  • itchy skin
  • swollen face or hands
  • difficulty swallowing

To diagnose a fever from Crohn’s, a doctor will first take your temperature and ask you how long you’ve been feeling feverish, and what readings you’ve been getting with a home thermometer.

It’s possible for Crohn’s disease to cause temperatures of 100°F (38°C) or higher. However, in most cases, Crohn’s disease causes low grade temperatures due to ongoing inflammation.

Since there are several causes of fever from Crohn’s, figuring out the exact trigger may involve a process of elimination. This can include ruling out an active infection or side effects from medications.

If a doctor suspects underlying complications from Crohn’s disease, you may need to undergo additional testing such as:

  • blood tests
  • imaging tests
  • endoscopy

Treatment and management of a fever with Crohn’s depends on the underlying cause, as well as where you are on your current Crohn’s disease treatment plan.

Newly diagnosed Crohn’s typically requires induction treatment of about 3 months. If you have a low grade fever as part of a new diagnosis, a doctor may focus on reducing inflammation with steroids and immunomodulators.

If you’ve passed the induction treatment phase, and still have a fever, your doctor might change your medications if they determine your Crohn’s is more moderate to severe. In such cases, biologics or biologics-immunomodulator combinations may be recommended.

An infection from Crohn’s disease or from a weakened immune system may be treated with antibiotics. If a doctor determines your medication is causing fever, they will likely change your treatment plan.

A doctor may recommend over-the-counter medications like acetaminophen (Tylenol). They will likely also recommend you drink plenty of fluids to help prevent dehydration.

Consider speaking with a doctor if you’re experiencing a fever with Crohn’s disease. They can help determine the underlying cause and offer treatments to help you feel better.

Also, seek immediate help if you think you’re experiencing side effects from biologics.

You should also get medical help if you’re experiencing the following symptoms:

  • diarrhea that lasts longer than 7 days
  • abdominal pain that doesn’t go away
  • blood in your stool
  • unintentional weight loss

When discussing a new or recurring fever and Crohn’s disease with a doctor, consider the following commonly asked questions:

How long does a fever last with Crohn’s?

The amount of time you experience fever with Crohn’s depends on the underlying cause. In the beginning stages of this condition, it’s possible to experience mild fever and GI symptoms that come and go for weeks and months at a time.

A fever related to an infection, on the other hand, may have a more sudden onset and get better once you’ve started taking antibiotics.

What causes Crohn’s fever at night?

A fever at night from Crohn’s disease could indicate systemic inflammation from the underlying condition, especially if you also experience night sweats.

What causes Crohn’s fever after eating?

While diet isn’t a direct cause of Crohn’s disease, it’s thought that certain foods might make symptoms worse. This may possibly include systemic inflammation symptoms, such as fever.

To help reduce Crohn’s symptoms, a doctor might recommend that you eat smaller, more frequent meals, drink more liquids, and decrease your fiber intake.

A Crohn’s disease fever may develop as a result of underlying inflammation related to this condition. In some cases, it can also indicate disease progression and complications. If you take certain medications, know that fever can also be a side effect.

See a doctor if you have a recurring or sudden fever with Crohn’s disease. They can determine the trigger of the fever and offer appropriate treatments to address the underlying cause and help you feel better.