Coughs are spreading at school and your child has a fever: when should you ask about a Mycoplasma test?

Hello. I am Shunichi Gamo, MD, PhD, a board-certified pulmonologist and the director of Sendai International Airport North Clinic.

When more children at school are coughing and your child also has a fever and cough that keep going, you may wonder, “Could this be Mycoplasma? Should my child be tested?” The short answer is that an outbreak at school is only one clue, and symptoms alone cannot determine the cause. The doctor decides whether a test is needed, based on how your child’s illness has developed. When you see the doctor, please describe how the illness has progressed so far.

This article explains how to think things through when Mycoplasma is suspected, the types of tests, and how to read the results. It also covers signs that mean you should get medical care quickly, what to tell the doctor, and what to check about treatment and returning to school after a diagnosis.

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When coughs are spreading at school, is your child’s fever caused by Mycoplasma?

When a child has a cough and fever that continue, Mycoplasma pneumoniae (usually just called Mycoplasma) may be one possible cause of pneumonia, but symptoms alone cannot determine the cause. One review article (a paper that summarizes the research done so far) looked at community-acquired pneumonia in children, meaning pneumonia caught in everyday life. It reports that viruses are the most common cause in children under 5, while in children 5 and older, Mycoplasma is an important bacterial cause along with pneumococcus. [1] The same review says that in many cases, symptoms and examination findings alone cannot reliably tell bacterial pneumonia from viral pneumonia. [1]

At the visit, please tell the doctor two things separately: how many children in the class are coughing, and how long your child’s own fever and cough have lasted.

What types of Mycoplasma tests are there, and what do they show?

Mycoplasma tests for children include tests for the germ’s genes, antibody tests (blood tests for antibodies made after infection), rapid antigen tests (quick tests for germ components), and culture (growing the bacteria to confirm them). [2] Two terms are useful here. Sensitivity is how often a test correctly gives a positive result in people who have the disease, and specificity is how often it correctly gives a negative result in people who do not. Among the tests listed above, PCR (a test that copies a germ’s genes so they can be detected) has high sensitivity and specificity and is regarded as the standard test for diagnosis. [2] Rapid antigen tests give results quickly, need no special equipment, and can be used for early diagnosis. [2] Culture is not recommended for routine diagnosis, because the bacteria take a long time to grow and its sensitivity is low. [2]

A report explaining testing methods notes that antibody tests can be negative early in the infection. [3] However, which tests are available differs from one medical facility to another. When you visit, please ask which tests are available at the facility where your child is being seen.

Test	What it looks for	Role in diagnosing Mycoplasma infection in children
PCR	Mycoplasma genes	Has high sensitivity and specificity and is regarded as the standard test for diagnosis. [2]
Rapid antigen test	Parts of Mycoplasma	Gives quick results, needs no special equipment, and can be used for early diagnosis. [2]
Antibody test	Antibodies in the blood	A report explaining testing methods notes that it can be negative early in the infection. [3]
Culture	The bacteria themselves	Not recommended for routine diagnosis, because the bacteria take a long time to grow and sensitivity is low. [2]

If the test is positive, does that mean Mycoplasma is causing the current fever and cough?

Even when a test is positive, that alone may not prove that the germ it found is causing the current illness. One study in the Netherlands looked at children aged 3 months to 16 years in hospital and after-hours general practice settings. It included 405 children with no symptoms and 321 children with respiratory symptoms. Mycoplasma genes were found in nose or throat samples from 21.2% of the children with no symptoms and 16.2% of the children with symptoms. [4] In the same study, measuring the amount of bacteria with PCR could not tell children carrying the bacteria without symptoms from children with a symptomatic infection, and neither could antibody tests or culture. [4]

As the researchers themselves point out, this study was done at a single research site and was limited in size. For that reason, the same rates cannot be applied to children in Japan. What matters is that the doctor looks at the whole picture. The doctor reads the test result together with how the fever and cough have changed, what the chest sounds like, and, if needed, imaging and other findings. When you get the result, please ask, “Does this result explain my child’s current symptoms?”

When should you ask about a Mycoplasma test, and what signs mean you need care quickly?

If the fever and cough continue, please ask the doctor whether a test is needed. If you have heard that Mycoplasma is spreading at school, please share that information too.

When to get care	Your child’s condition
Seek medical care right away (even at night or on a holiday)	Fast breathing, shoulders moving up and down to breathe, chest sinking in when breathing in, bluish-purple or pale lips or face, very limp and unable to drink, slow to respond when called, or a seizure
Contact a medical facility soon	If the fever and cough continue and you are worried, if the cough is getting worse day by day, or if the fever continues after starting medicine, please talk to your regular doctor. If Mycoplasma is spreading at school or at home, please mention that as well.
Watch your child and consider a visit	Your child is active and drinking, and the fever is coming down, but the cough remains. If things change, such as the cough getting worse or the fever coming back, see a doctor soon. If your child seems to be struggling to breathe, that belongs under “Seek medical care right away,” not this row.

If your child seems to be struggling to breathe, looks pale, or is very limp and unable to drink, please get medical care even at night or on a holiday. Do not wait for morning or for regular clinic hours.

What should you tell the doctor when asking about a Mycoplasma test?

A review notes that in children, symptoms and examination findings alone cannot reliably tell whether pneumonia is caused by bacteria or by a virus. [1]

At the visit, it helps to tell the doctor not only that something is spreading at school, but also how your child’s own illness has developed, in time order. Whether to test, and which test to use, is decided by looking at your child’s age, how the symptoms have developed, any medicine already taken, and what is going around nearby. If you write a note before the visit, using the table below as a guide, you are less likely to forget to mention something.

What to tell the doctor	Example note
The day the fever and cough started	Cough since Monday, fever since Wednesday night
Type of cough and how it has changed	Dry cough, bad at night, getting worse each day
Illness going around	Several children in the class are coughing; a brother or sister is coughing too
Medicines being taken	Name of the medicine, the day it was started, whether your child is able to take it
Eating, drinking and sleep	Drinking fluids well; eating about half as much as usual
Ongoing conditions and allergies	Whether your child has asthma; any drug allergies

Here are four questions you may want to ask in the exam room.

• Given how the illness has gone, could this be pneumonia or Mycoplasma?
• If a test is done, which test will it be, and when will the result be ready?
• How will the treatment change depending on the result?
• What changes should make us come back, and when should our next visit be?

If your child is diagnosed with Mycoplasma, how does treatment go, and what if the fever does not come down?

For Mycoplasma pneumonia in children, the first choice among antibacterial drugs (commonly called antibiotics) is considered to be macrolides (the type of antibiotic used first for Mycoplasma). [5] However, if the Mycoplasma has become resistant, meaning macrolides no longer work well against it, the fever may last longer. There are also results from a systematic review and meta-analysis (a study that combines the results of several studies using statistics). Children infected with Mycoplasma that macrolides do not work well against had a fever that lasted 1.71 days longer than children whose infection responded to the medicine. [6]

A review notes that the share of resistant bacteria varies greatly by country and region: the large majority are resistant in East Asia, while the share is much lower in Europe and North America. [5] So the rates in other countries or regions cannot be applied directly to children in Japan. Please ask your medical facility about the situation in Japan. If the fever does not come down after starting the medicine, do not just wait; go back to the doctor so the treatment can be reviewed. At that visit, please show a note with the medicine’s name, the day it was started, whether your child has been taking it properly, and how the fever has changed.

Tetracyclines (another type of antibiotic) are an alternative when macrolides do not work, but they are not recommended for children under 8. [2] The doctor chooses the medicine based on your child’s age and course of illness. Please do not stop the medicine on your own, and do not use leftover medicine from a past illness.

If your child is diagnosed with Mycoplasma, when can they go back to school?

Unlike influenza, Mycoplasma pneumonia has no fixed number of days that a child must stay home from school under the rules. This is because Mycoplasma is not one of the Category 2 infectious diseases. For those diseases, the Enforcement Regulations of Japan’s School Health and Safety Act set the absence period for each type. Category 3 infectious diseases include “other infectious diseases.” For these, the standard for required absence is “until a school physician or other doctor judges, based on the child’s condition, that there is no risk of spreading the infection.”

The website of Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) links to a guide from the Japanese Society of School Health, the “Guide to Infectious Diseases That Should Be Prevented at School.” This guide gives a standard for returning to school after Mycoplasma infection. Its wording is: “A child whose symptoms have improved and whose general condition is good may attend school (or preschool).” According to the same guide, “other infectious diseases” are not specific diseases decided in advance. Rather, the category is a system that lets the principal take emergency measures, after hearing the school physician’s opinion, when a serious outbreak occurs at a school. Also, whether to instruct a child to stay home because of Mycoplasma is decided by considering how widespread it is in the area or at the school.

When your child goes back to school, please check with the doctor that the symptoms have improved and that your child’s general condition is good. Schools handle required absence differently, so if the school gives you instructions, please follow them. If the school has asked for a document allowing your child to return, please mention this at the visit.

Summary

• When coughs are spreading at school and a child has a fever, Mycoplasma is one possible cause of pneumonia, but symptoms alone cannot determine the cause.
• Tests include PCR, antibody tests and rapid antigen tests. A positive result alone may not prove the cause, so the doctor reads it together with the course of illness.
• If your child has trouble breathing or looks pale, please get medical care even at night or on a holiday. If the fever and cough continue, talk to a doctor soon, bringing information about the outbreak and about how your child’s illness has progressed.
• If the fever continues after starting antibiotics, go back so the doctor can review the treatment, including the possibility of resistant bacteria.
• Returning to school is not decided by a fixed number of days set by rules. It depends on improvement in symptoms, general condition and the school’s decision.

Frequently asked questions

Mycoplasma is spreading at my child’s school. Should my child be tested as soon as a fever starts?

A test is not always needed from the first day of fever. Mycoplasma is one of the important causes of pneumonia in children 5 and older, but it is considered hard to tell from symptoms alone whether pneumonia is caused by bacteria or a virus. [1] If the fever and cough continue, or if your child seems to have trouble breathing, tell the doctor about the outbreak along with how the illness has progressed. Then ask during the visit whether a test is needed.

If a Mycoplasma test is positive, is Mycoplasma always the cause?

Not necessarily. In a Dutch study, Mycoplasma genes were found in the nose or throat of 21.2% of children with no symptoms and 16.2% of children with symptoms. [4] The doctor reads the test result together with the course of the fever and cough. When you get the result, please ask whether the result explains the symptoms.

My child is taking medicine for Mycoplasma, but the fever is not coming down. Should we switch medicines right away?

Please do not switch or stop the medicine on your own. Go back and have the doctor check how the illness is going. One analysis found that when macrolide antibiotics do not work well against the Mycoplasma, the fever lasts longer than when they do work. [6] At the follow-up visit, please tell the doctor the medicine’s name, the day it was started, and how the fever has changed.

Disclaimer

This article provides general medical information. It does not replace an examination, diagnosis or treatment by a doctor. The content is based on medical knowledge at the time of publication, but the right approach differs with each patient’s condition and background.

If you are worried about your symptoms, please talk to your regular doctor or a specialist medical facility.

References

1. Leung AKC, Wong AHC, Hon KL. “Community-Acquired Pneumonia in Children.” Recent Pat Inflamm Allergy Drug Discov, 2018; 12(2): 136-144. DOI: 10.2174/1872213X12666180621163821 PMID: 29932038
2. Gao L, Sun Y. “Laboratory diagnosis and treatment of Mycoplasma pneumoniae infection in children: a review.” Ann Med, 2024 Dec; 56(1): 2386636. DOI: 10.1080/07853890.2024.2386636 PMID: 39097794
3. Wang Y, Xue C, Luo Q, Ma J, Zeng X. “Detection of Mycoplasma pneumoniae Nucleic Acid and Drug Resistance Gene.” J Vis Exp, 2025 Sep 19(223). DOI: 10.3791/68500 PMID: 41051998
4. Spuesens EB, Fraaij PL, Visser EG, Hoogenboezem T, Hop WC, van Adrichem LN, et al. “Carriage of Mycoplasma pneumoniae in the upper respiratory tract of symptomatic and asymptomatic children: an observational study.” PLoS Med, 2013; 10(5): e1001444. DOI: 10.1371/journal.pmed.1001444 PMID: 23690754
5. Ding G, Zhang X, Vinturache A, van Rossum AMC, Yin Y, Zhang Y. “Challenges in the treatment of pediatric Mycoplasma pneumoniae pneumonia.” Eur J Pediatr, 2024 Jul; 183(7): 3001-3011. DOI: 10.1007/s00431-024-05519-1 PMID: 38634891
6. Chen YC, Hsu WY, Chang TH. “Macrolide-Resistant Mycoplasma pneumoniae Infections in Pediatric Community-Acquired Pneumonia.” Emerg Infect Dis, 2020 Jul; 26(7): 1382-1391. DOI: 10.3201/eid2607.200017 PMID: 32568052