What causes fever? 221 possible conditions

See a list of possible causes in order from the most common to the least.

21

Appendicitis

This condition is considered a medical emergency. Urgent care may be required.

Appendicitis is inflammation of the appendix, which can be fatal if left untreated. The telltale sign is pain that usually starts as mild cramping, especially on the right side, and becomes more severe over time.

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22

Swine Flu

Swine flu, also known as H1N1, is a highly contagious virus with symptoms similar to common influenza types. It spreads quickly from person to person, and can linger on tables and surface areas.

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23

Tonsillitis

Tonsillitis occurs when the tonsils (the lymph tissue in your throat) become infected. Symptoms include sore throat, fever, and swollen tonsils. Fortunately, it's normally easily diagnosed and treated.

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24

Viral Gastroenteritis

Viral gastroenteritis, also known as the stomach flu, is caused by a number of different viruses. Its symptoms usually last for two to three days.

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25

Infectious Mononucleosis

Infectious mononucleosis, or "mono," is a group of symptoms caused by the Epstein-Barr virus. One potential symptom is a pink rash that looks like the measles.

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26

Pyelonephritis

Pyelonephritis is an inflammation of the kidney and upper urinary tract. Symptoms include flushed skin, back pain, fever, and nausea.

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27

The Atypical Facts About Atypical Pneumonia

Atypical pneumonia that is caused by mycoplasma bacteria, one possible symptom is a rash.

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28

Pharyngitis

Pharyngitis is inflammation of the pharynx (the back of the throat). This can cause soreness, scratchiness, and difficulty swallowing. Most cases occur during colder months when the humidity is low.

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29

Chickenpox

Also known as varicella, chickenpox is a virus that often affects children. It is characterized by itchy, red blisters that appear all over the body.

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30

Cellulitis

Cellulitis is a common, often painful skin infection that first appears as a red, swollen area that feels hot and tender to the touch. If left untreated, it can become life-threatening.

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31

Epiglottitis

This condition is considered a medical emergency. Urgent care may be required.

Epiglottitis is a life-threatening condition characterized by inflamed epiglottis tissue. Once the airway becomes blocked, an adult or child may exhibit bluish discoloration of their skin or lips from lack of oxygen.

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32

Measles

Measles is a very contagious infection of the respiratory system. One of its several symptoms is a sore or swollen throat.

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33

The Many Sides of Bacterial Gastroenteritis

Bacterial infections are common causes of gastrointestinal infections. This type of infection is also called "food poisoning" and is often caused by poor hygiene or ingesting foods contaminated with bacteria.

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34

Crohn’s Disease

Crohn's disease is a chronic bowel disease that causes severe inflammation of the digestive tract. It is associated with abdominal pain, diarrhea, and may affect your quality of life. Crohn's disease is characterized b...

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35

Pelvic Inflammatory Disease (PID)

Pelvic inflammatory disease (PID) is an infection of the reproductive organs in women caused by bacteria. It's marked by pain in the abdomen, especially during urination or sex.

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36

Fifth Disease

Fifth disease is caused by a virus and mostly affects children. The disease is marked by feeling unwell, often followed by a red rash on the cheeks.

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37

German Measles (Rubella)

German measles, also known as rubella, is a rare viral condition. One of its symptoms is a pink rash that begins on the face and spreads downward.

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38

Empyema

Empyema is a collection of pus inside a body cavity, typically inside the pleural cavity, between the surface of the lungs and the inner lining of the chest wall. It can cause fever, cough, chills, and other symptoms.

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39

Rhinitis

Rhinitis is inflammation of the nasal cavity lining (inside the nose). It is often caused by allergies. It may also be caused by environmental factors such as pollution, weather changes, stress, infections, and som...

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40

CFS (Chronic Fatigue Syndrome)

Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by intense fatigue that cannot be cured with sleep. Mental and physical activities may cause symptoms to worsen. When fatigue cannot be linked to ...

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.
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