"Not again," he thought as he started to get a sore throat on a rainy October afternoon. The 7-year-old knew what to expect. His knees would start to ache and soon he would be burning with a high fever.

He dreaded taking his temperature and watching his mother's eyes widen as the probe raced through the normal range to reach 102, 103, 104, and sometimes even 105 degrees Fahrenheit.

As though on cue, he awoke the next morning to find his knees and ankles were bothering him and he had a high fever. Even the prospect of missing the scheduled spelling test in school didn't offer much pleasure; instead, he spent much of the day alternating between doses of Tylenol and ibuprofen to get some relief.

His condition only worsened, and soon he was complaining of pain in all his joints. Besides his sore throat, he noticed a few painful canker sores in his mouth.

The fevers and other symptoms lasted three to four days before resolving. Even after the fevers subsided, he was left feeling completely exhausted for several days. These cyclic episodes had been going on for as long as he could recall; his parents pinpointed his first episode at age 2.

In the past when the fevers would come on, his parents would drag him to the pediatrician's office. The pediatrician would ask many questions, only to hear the same story again and again. Initially, these visits to the doctor were always accompanied by a battery of tests including blood work, urine samples, and occasionally a chest X-ray. The only significant lab abnormality would be an elevated white blood cell count, which often is a marker of infection but which can also be seen in periods of stress or even chronic diseases.

Sometimes, he would get antibiotics in an attempt to see whether the fevers would resolve sooner - they didn't - but most of the time, the diagnosis was presumed viral infection.

The boy and his parents had become resigned to simply waiting out the episodes, given that the fevers usually went away after a few days. But this time, as the fevers and joint pains persisted into a fourth day, the boy was feeling more wiped out than usual. He had already missed almost a week of school and was in danger of missing a soccer game. His mother called the pediatrician's office again to see whether there was anything else that could be tried to help her son recover faster.

The pediatrician took some time to review the child's case. She finally had a suggestion to offer the family and prescribed a medication for the patient to take that evening.

When the pediatrician called the child's home the next day, she was surprised to learn the boy wasn't home. His fevers had resolved soon after taking the medication, and he had felt well enough to go to school that morning.

What medication had the doctor prescribed? What did the child have?

Solution:

As the pediatrician was reviewing the child's medical chart, she was struck by how periodic the fever episodes were.

She recalled learning about a family of diseases called recurrent fever syndromes that typically presented during childhood. The most common is familial Mediterranean fever (FMF). But this patient didn't meet the classic ethnic profile. The disease occurs mainly among ethnic groups originating in the Mediterranean, such as Sephardic Jews, Turks, North Africans, Arabs, and, less commonly, Italians and Greeks. Also, most patients with FMF have abdominal or chest pain during the fever episodes, which this patient did not have.

Another similar syndrome with a rather descriptive name is Periodic Fever with Associated Aphthous Stomatitis, Pharyngitis, and Adenitis (PFAPA). That was a perfect match for this patient.

Patients with PFAPA typically experience cyclic episodes of fever that last three to six days starting in childhood. Along with fever, patients will have pharyngitis (inflammation of the throat), mild aphthous ulcers (mouth sores), adenitis (swollen lymph nodes), fatigue, and joint pains. Many children, though, may have only one or two of these symptoms along with fever. The workup is often unrevealing except for elevated white blood cell counts as well as blood tests for inflammation in the body during the acute episodes. These laboratory abnormalities usually go back to normal in between attacks. In addition, patients grow and develop normally despite these recurrent fevers.

Typically, patients outgrow the fever episodes in time. In fact, this patient had noted the attacks were becoming less frequent as he got older. An important feature of PFAPA is that the symptoms, including fevers, resolve promptly with a single dose of prednisone, a type of steroid that can rapidly decrease inflammation in the body. This is what the pediatrician had prescribed, and the patient's dramatic improvement led to the diagnosis of PFAPA.

With the diagnosis, the pediatrician recommended the boy take a single dose of prednisone whenever he started noting the onset of a fever attack. She remained optimistic that the fever episodes would resolve completely as the boy got older.

Dr. Gowda is a fellow in infectious diseases at the University of Pennsylvania; Dr. Sherry is director of clinical rheumatology at Children's Hospital of Philadelphia.