Almost every child will get a fever, a body temperature over 100 degrees F, at some time or another. Usually, the fever clears up within a day or two. If your child frequently experiences a fever or one that occurs without an accompanying infection, it may be a sign of a serious condition.

Symptoms

The most obvious symptom of a fever is an increase in body temperature, determined by a thermometer. Accuracy varies based on where you take a child’s temperature. A child with a rectal temperature of 100 degrees F has a fever and a child with an armpit temperature of 99.5 degrees F also has a fever. Other common symptoms of a fever include irritability and a lack of interest in activities.

Types and Causes

Recurring fever can occur over the course of a single illness or can involve several separate infections that each feature a fever as a primary symptom. In some cases, your child’s recurrent fever could be caused by an auto immune disorder, such as lupus, according to Dr. Sarah S. Long, writing for Pediatric Clinics of North America. Your child may also have been exposed to a rare infection, such as malaria. Chronic infections, such as a recurrent urinary tract infection or a sinus infection, can also lead to recurring fevers, according to Long.

Periodic Fever

Sometimes, a recurring fever may be a sign of a serious condition that is not caused by an infection. A child whose fevers recur at regular intervals, as if following a specific schedule, may have a periodic fever syndrome, such as familial Mediterranean fever, periodic fever, aphthous-stomatitis, pharyngitis, adenitis (PFAPA) or cyclic neutropenia, according to the Cleveland Clinic. Periodic fever syndromes usually run in families and some have specific symptoms in addition to fever. PFAPA is the most common, according to Long.

Diagnosing and Testing for Periodic Fever

Although it is the most common, there is no test for PFAPA. Your doctor may diagnose your child with the syndrome if he experiences more than three episodes of fever that last for five days as well as a sore throat, mouth sores and swollen lymph nodes, according to the Merck Manual. Familial Mediterranean fever and other genetic syndromes are usually diagnosed through blood and genetic testing as well as by examining the family history and a patient’s symptoms.

Treatment

Treatment options vary, depending on the cause of your child’s recurring fever. In some cases, your child’s immune system will simply develop enough that he is able to ward off infections that caused the fevers. If the fevers are caused by an autoimmune condition, he will need medications designed to treat the condition. In the case of some periodic fevers, such as PFAPA, your child may simply outgrow the syndrome, according to the Merck Manual. Anti-inflammatory, colchicine, can help treat other syndromes.