Common Causes of Fever

Fever is the common denominator for a lot of childhood illnesses. As mentioned previously, autoimmune disorders, infections, or even a reaction to medication can trigger a fever. This section focuses on a few common causes of fever.


Roseola is perhaps one of the most common causes of fever for children. The fever that is associated with roseola typically spikes suddenly, and it is usually very high (104ºF is not uncommon). Despite the high fever, the child often appears comfortable and playful. The fever is frequently followed by an eruption of rash though this does not occur in everyone. It is entirely possible to have roseola with just the fever and with no rash at all.

As with most fevers triggered by a viral infection, the duration of the fever is normally short (less than four days). Occasionally, it can last seven days, which would prompt most physicians to conduct investigative blood and urine tests.

Urinary Tract Infections

Urinary tract infections (UTIs) are the type of bacterial infection that most commonly requires hospitalization for children. Children younger than six months are routinely managed with inpatient care and intravenous antibiotics. The reason pediatricians treat urinary tract infections seriously is because if the infection spreads to the kidneys, permanent kidney damage can result. If the kidney infection is severe enough, kidney function may fail completely, requiring the patient to stay on dialysis indefinitely.

If your toddler has a fever for more than three days but has no other symptoms (such as a runny nose, cough, vomiting, or diarrhea), you should bring him to the doctor's office to make sure there is no bacterial infection or UTI present. Keep in mind that before your child is potty-trained, the only way to obtain an urine specimen from him may be via catheterization of the bladder.


Children over three years old can reliably report a painful sensation with urination when they have a UTI. Unfortunately, younger children cannot usually vocalize their discomfort. As a result, any child under the age of two with a high fever (greater than 101°F) without any apparent source for the fever needs to have her urine examined for evidence of infection.


Mononucleosis, simply called “mono” by most people, is another viral infection that can cause a prolonged fever without any apparent source. Mononucleosis most commonly affects older children, adolescents, and even adults. People who come down with this infection usually feel extremely tired as well as feverish. Many have some degree of soreness in the throat during the initial phase of the infection, and most also have enlarged glands around the neck.

Scarlet Fever

Scarlet fever is nothing more than a strep throat run rampant. It used to be a life-threatening infection, but over the past century, the strain of bacteria that causes the infection has become significantly weaker. No one knows why this is so, but scarlet fever no longer causes death in children.

Scarlet fever usually starts out as a run-of-the-mill strep throat. Soreness in the throat, fever, and nasal congestion are common initial symptoms. However, when the toxin made by the strep bacteria spreads into the bloodstream, scarlet fever occurs.

The rash associated with scarlet fever is very rough. When you run your finger across the surface of the skin, it almost feels like sandpaper. The rest of the skin is typically very red, similar to a bad sunburn. The fever coexists with the rash, and a general sensation of fatigue is common.

If you suspect your child might have scarlet fever, you need to get an appointment with your doctor within a few days. Even though scarlet fever is no longer a lethal infection, untreated scarlet fever or strep throat can sometimes cause rheumatic fever or glomerulonephritis, conditions that occur when the immune system inappropriately attacks the heart or the kidneys, respectively.

  1. Home
  2. Childhood Illnesses
  3. The Fever Fear
  4. Common Causes of Fever
Visit other sites: