Fevers are your child’s first line of defense against bacteria and viruses. But what does it mean when they keep getting fevers, even if they’re no longer sick? They may have recurrent fever syndrome (previously known as periodic fever syndrome), a disorder that causes inflammation and fevers that come and go but no other obvious symptoms of infection. Some research suggests that these fevers can sometimes be related to COVID-19 or long COVID.

In this article, we’ll discuss what recurrent fever syndrome is, the different types, and how it may be related to COVID-19. We’ll also cover when to talk to your child’s pediatrician and how they’ll treat their fevers.

What Are Recurrent Fever Syndromes?

Recurrent fever syndromes are a group of conditions that cause repeated episodes of fever over time. Your child’s body raises its temperature to fight off invading bacteria and viruses. In recurrent fever syndromes, your child develops a fever without an infection.

These conditions are considered autoinflammatory diseases, which are different from autoimmune diseases. In autoimmune diseases, the immune system mistakenly attacks the body's own healthy cells. Recurrent fever syndromes don’t involve this kind of self-attack. Instead, they cause repeated episodes of fever without a clear reason.

Types of Recurrent Fever Syndromes

There are five main types of recurrent fever syndrome:

• Periodic fever, aphthous-stomatitis, pharyngitis, adenitis (PFAPA)
• Familial Mediterranean fever (FMF)
• Hyperimmunoglobulin D syndrome (HIDS)
• Tumor necrosis factor receptor-associated periodic syndrome (TRAPS)
• Neonatal onset multisystem inflammatory disease (NOMID)

The most common type is FMF, which affects roughly 1 in 200 people of Middle Eastern and Mediterranean descent, according to Cleveland Clinic. TRAPS, HIDS, and NOMID are caused by genetic changes. These changes are inherited, meaning they can be passed down from parents to children.

On the flip side, doctors are still trying to figure out the exact cause of PFAPA. It doesn't seem to be linked to any specific genetic changes.

Symptoms of Recurrent Fever Syndromes

You’ve likely heard that the average body temperature is 98.6 Fahrenheit, but it can range anywhere from 97 F to 99 F — or higher. A fever is typically considered to be a temperature of 100.4 F or higher. For children with recurrent fever syndrome, their temperatures go as high as 104 F or 105 F.

In addition to fever, recurrent fever syndromes can cause other bodywide symptoms. They vary by the type of condition and include:

• PFAPA — Mouth sores, sore throat, and swollen lymph nodes
• FMF — Inflammation leading to joint pain and swelling, abdominal pain, skin rashes on the ankles or lower half of the legs
• HIDS — Flu-like symptoms, abdominal pain, loss of appetite, headaches, painful ulcers, and chills
• TRAPS — Muscle pain in your child’s arms and midsection, chills, and a painful, discolored skin rash
• NOMID — Skin rash that looks similar to hives

Symptoms of periodic fever syndromes can last for several days, then suddenly disappear on their own.

Recurrent Fever Syndrome and COVID-19

Unfortunately, there currently aren’t any large studies showing a strong connection between recurrent fever syndrome and COVID-19 in children. Doctors and researchers may continue to look further into these conditions as they learn more about the long-term effects of COVID-19 and long COVID.

Here are three facts about recurrent fever syndrome and how it may be connected to COVID-19.

1. Recurrent Fevers May Be a Symptom of Long COVID in Children

Symptoms of COVID-19 can linger long after the infection is cleared. This condition is known as long COVID, and it’s less common in children than adults. One review of 21 studies found that around 25 percent of children who contract COVID-19 develop long COVID.

The most common symptoms seen were fatigue, sleep disorders, and mood changes. Of the children with long COVID, only around 2 percent had recurring fevers. The authors also found that children who had COVID-19 were more likely to have fevers compared to those who hadn’t.

If your child keeps getting fevers even after recovering from COVID-19, speak with their pediatrician. They may recommend testing for specific genetic factors. One key gene, MEFV, controls a protein known as pyrin that helps regulate the body’s natural defense system. Research suggests that abnormalities in this gene could lead to recurring fevers.

2. COVID-19 May Worsen Recurrent Fever Syndrome Symptoms

Recurrent fever syndromes aren’t caused by infections, but a virus may worsen symptoms. One study looked at 73 teenagers and adults with FMF to see how COVID-19 affected their condition. Recurrent fever syndrome is typically diagnosed in childhood, and it can continue through adolescence and adulthood.

The authors found that one-third of the participants experienced worse symptoms after a COVID-19 infection. Examples included fever, inflammation in the lungs, and joint pain. While this study didn’t involve young children and had some teenagers, it shows that COVID-19 may trigger fevers in people with FMF or other types of recurrent fever syndrome.

3. Stress From the COVID-19 Pandemic May Have Been a Trigger for PFAPA

Emotional stress is a known trigger of PFAPA and other autoinflammatory diseases. When the COVID-19 pandemic first began, children were taken out of school and away from their normal routines and friends. This created stressful situations that seemed to increase PFAPA symptoms.

Researchers conducted a study of 99 children between the ages of 3 and 12 who were previously diagnosed with PFAPA. They found that emotional distress triggered more PFAPA attacks during the pandemic.

If your child is experiencing any extra stress and begins developing fevers or other signs of recurrent fever syndrome, you can bring it up to their pediatrician.

Talk to Your Child’s Pediatrician About Recurrent Fevers

If your child has had recurring fevers after a COVID-19 infection — or other signs of long COVID — it’s best to talk with their pediatrician. They may want to do genetic testing to see if your child has a genetic form of recurrent fever syndrome. This may be the case if they’re having frequent fevers and if recurrent fever syndrome runs in your child’s family. Being of Middle Eastern or Mediterranean descent may also be a risk factor.

Although there’s no cure for recurrent fever syndrome, it can be managed well with medications. The treatments vary depending on the type of condition your child has. Examples include:

• Colchicine (Colcrys, Gloperba) to treat FMF
• Steroids to treat inflammation in PFAPA
• Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) to treat HIDS
• Canakinumab (Ilaris) to treat HIDS, TRAPS, and NOMID

Your child’s pediatrician can also prescribe treatments to help manage their other long COVID symptoms. Together, you can find a plan that works best for your child to help them feel better.

Talk With Others Who Understand

On myCOVIDteam, more than 8,500 members come together to ask questions, give advice, and share their stories with others who understand life with COVID-19.

Has your child been diagnosed with recurrent fever syndrome and/or long COVID? Share your experience in the comments below, or start a conversation by posting on your Activities page.