Merck Manual

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Some Common Causes and Features of Fever in Children

Some Common Causes and Features of Fever in Children


Common Features*


Acute fever (lasting 14 days or less)

Respiratory infections due to a virus

A runny or congested nose

Usually a sore throat and cough

Sometimes swollen lymph nodes in the neck, without redness and tenderness

A doctor’s examination

Sometimes testing of swab of nasal mucus

Other infections due to a virus

In some infants or children, no symptoms except fever

A doctor's examination


Often vomiting

Possibly recent contact with infected people or certain animals or consumption of contaminated food or water

A doctor’s examination

Sometimes examination and testing of stool

Pain in one ear (difficult to detect in infants and young children who do not talk)

Sometimes rubbing or pulling at the ear

A doctor’s examination

A red, swollen throat

Pain when swallowing

A doctor’s examination

Sometimes a throat culture or rapid strep test (both done on a sample taken from the back of the throat with a swab)

In children under 3 years old

No other symptoms

Blood tests

Cough and rapid breathing

Often chest pain, shortness of breath, or both

A doctor's examination

Usually a chest x-ray

A red, painful, slightly swollen area of skin

A doctor’s examination

Pain during urination

Sometimes blood in urine

Sometimes back pain

In infants, vomiting and poor feeding

Urine tests

Infants: Sometimes bulging of the soft spots (fontanelles) between the skull bones, sluggishness (lethargy) or inconsolability

Older children: Headache, confusion, or lethargy

A spinal tap (lumbar puncture)

Newborns: Bulging of the soft spots (fontanelles) between the skull bones, inconsolability, poor feeding, and/or lethargy

Infants: Fussiness and irritability especially when held, inconsolability, poor feeding, and/or lethargy

Older children: Headache, sensitivity to light, lethargy, vomiting, and/or a stiff neck that makes lowering the chin to the chest difficult

A spinal tap


Recent vaccination

A doctor’s examination

Certain drugs

Recent addition of a new drug

A doctor’s examination

Fever for more than 5 days

Red eyes, lips, and tongue

Painful swelling of hands and feet

Often a rash

Sometimes swollen lymph nodes in the neck

A doctor's examination

Blood tests

ECG and echocardiography

Sometimes urine tests, ultrasonography of the abdomen, or an eye examination

Swollen, painful joints

New heart murmur detected during a doctor's examination

Sometimes a rash or bumps under the skin

Sometimes jerky, uncontrollable movements or changes in behavior

Often a history of strep throat

Blood tests

A throat culture

ECG and echocardiography

Chronic fever (lasting more than 14 days)

Infections due to a virus, such as

Long-lasting weakness and tiredness

Sometimes swollen lymph nodes in the neck, a sore throat, or both

Sometimes yellow discoloration of the whites of the eyes (jaundice)

Blood tests

Intermittent headaches, a runny nose, and congestion

CT of the sinuses

Abdominal pain and often tenderness to the touch

CT of the abdomen

Swollen, red, painful joint

Testing of a sample of fluid taken from the joint with a needle

Pain in affected bone

Sometimes a skin infection near the affected bone

Bone scan, MRI of bone, or both

Sometimes biopsy of bone to check for bacteria (culture)

Sometimes a heart murmur

Blood tests for bacteria (blood culture)


Poor weight gain or weight loss

Night sweats


Chest x-ray

Skin tests

Possibly culture of a sputum sample, and/or blood tests

A shaking chill followed by a fever that can exceed 104° F (40° C)

Fatigue and vague discomfort (malaise), headache, body aches, and nausea

Blood tests

Sometimes headache and neck pain

Sometimes a swollen, painful joint (such as the knee)

Sometimes a bull’s-eye rash in one or more locations

Occasionally a known history of a tick bite

A doctor's examination

Sometimes blood tests

Often a swollen, painful lymph node

Sometimes a bump on the skin where scratched by a cat

Blood tests

Blood in stool, crampy abdominal pain, weight loss, and loss of appetite

Sometimes arthritis, rashes, sores in the mouth, and tears in the rectum


Sometimes CT or x-rays after barium is inserted in the rectum (barium enema)

Joint and connective tissue disorders, such as

Swollen, red, tender joints

Often a rash

Sometimes fatigue

Blood tests

Cancer, such as

Poor weight gain or weight loss and loss of appetite

Night sweats

Possibly bone pain

A complete blood cell count

Removal (aspiration) of a sample of bone marrow for examination

Sometimes a bone scan, and/or MRI of bone

Sometimes CT of the chest or abdomen

Periodic fever syndromes, such as

Fever that recurs in often predictable cycles with periods of wellness in between

Sometimes mouth sores, sore throat, and swollen lymph nodes

Sometimes chest or abdominal pain

Sometimes family members who have had similar symptoms or have been diagnosed with one of the familial periodic fever syndromes

A doctor's examination during episodes of fever

Blood tests during and between fever episodes

Sometimes genetic testing

Usually a misinterpretation of normal fluctuations in body temperature or overinterpretation of frequent, minor viral illnesses

Usually no other symptoms of concern

Normal examination findings

A doctor's examination

Thorough and accurate recording of illnesses and temperatures as well as a description of the overall function of the child and family

Occasionally blood tests to rule out other causes and reassure parents

* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. Disorders that cause chronic fever also cause fever during the first 7 to 10 days.

CT = computed tomography; ECG = electrocardiogram; MRI = magnetic resonance imaging.