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What causes fever and headache? 78 possible conditions

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


Common Cold Overview

The common cold is a virus that involves symptoms like sneezing, a runny nose and a headache. Learn the causes, symptoms and treatments for the common cold now!

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Cold and Flu Overview

Common colds and influenza are contagious infections that affect the respiratory system. Both are airborne illnesses, spread through coughing and sneezing. Shared symptoms include headache, cough, sore throat, and more.

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Sinus Infections (Sinusitis)

A sinus infection causes the sinuses and nasal passages to become inflamed. Facial swelling is a common sign of this type of infection.

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Strep Throat

Strep throat is a bacterial infection that causes inflammation and pain in the throat. It's especially common in children. Look out for sudden fever, a red throat with white patches, headache, and chills.

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Acute HIV Infection

Acute HIV infection is the primary stage of infection by the human immunodeficiency virus. There are several telltale symptoms, one of which is a rash.

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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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Dengue Fever

Dengue fever is a disease that affects much of the tropical region and is caused by one of four dengue viruses. A skin rash between two and five days after the initial fever is a common symptom.

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Food Poisoning

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

Food poisoning occurs when you consume foods contaminated with bacteria, viruses, or parasites. Symptoms are usually uncomfortable but not severe.

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Pneumonia is an infection of the lungs caused by fungi, bacteria, or viruses. General symptoms include chest pain, fever, cough, and difficulty breathing.

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Malaria is a life-threatening disease. It is typically transmitted through the bite of a mosquito infected with Anopheles. Nausea, chills, fever, and diarrhea are common symptoms.

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

Meningitis is an inflammation of the membrane that covers the brain and spinal cord. It may cause headache and fever in teens and adults, irritability in babies, and trouble breathing in young children.

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Caffeine Overdose

The recommended amount of caffeine is usually 400 mg per day for healthy adults. Caffeine overdose may occur if you ingest more than this amount.

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Heat Emergencies

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

Heat emergencies are health crises caused by exposure to hot weather and sun. Heat emergencies have three stages: heat cramps, heat exhaustion, and heatstroke. All three stages are serious.

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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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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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The Atypical Facts About Atypical Pneumonia

Pneumonia is an infection that causes inflammation of the lungs. Atypical pneumonia is a kind that isn't caused by the bacteria that causes typical pneumonia.

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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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Pharyngitis is inflammation of the pharynx, which is in the back of the throat. It's most often referred to simply as "sore throat" and is very common.

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CFS (Chronic Fatigue Syndrome)

Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by extreme tiredness that can't be explained by an underlying medical condition.

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