Diagnosis is not based solely on the appearance of the lesions. A mycological sample can confirm the infection and guide the choice of treatment. Professor Annabel Maruani-Raphael, head of the pediatric dermatology unit at the Tours CHRU, recalls the signs to recognize and the precautions to take.
Patches, scales, broken hair: signs that should alert you
A small plaque on a child’s head may seem innocuous. However, when it is accompanied by scales, itching or broken hair, it deserves special attention. These manifestations may be those of ringworm, a scalp infection caused by microscopic fungi called dermatophytes.
These fungi have a particular affinity for keratin, a protein that makes up hair. In affected areas, hair may break near the root, making it appear as if parts of the scalp have been shorn. One or more plaques may appear.
But not all scalp lesions are ringworm. Alopecia areata or eczema can present similar aspects. A medical examination is therefore necessary to distinguish these conditions and avoid missing the correct diagnosis.
Ringworm is more common in children than adults. Close contact, particularly at school or during play, facilitates its transmission from one child to another. It can also be transmitted from animals to humans, for example from a cat, a dog or livestock. More rarely, contamination can come from the earth.
This diversity of possible sources explains why it is important not just to note the lesions: it is also necessary to determine which fungus is involved.
Why a sample is essential to choose the right treatment
Even when the appearance of the scalp strongly suggests ringworm, the doctor must, as much as possible, confirm the diagnosis with a mycological sample, taken as soon as possible.
The sample is first examined under a microscope by a biologist, then cultured. This second stage generally takes three to four weeks. It makes it possible to identify the responsible dermatophyte and guide treatment.
Two genera of fungi are mainly involved:
Trichophyton And Microsporum. Their identification matters, because the choice of medication and duration of treatment may vary depending on the fungus responsible.
This wait does not necessarily mean that support must remain suspended for several weeks. Depending on the situation, the doctor may start treatment before receiving the results and then adapt it if necessary.
The objective is twofold: to effectively treat the infection and limit its transmission. Because insufficiently treated ringworm can persist, while close contact can promote its spread.
A treatment over several weeks, to be adapted to each child
The management of ringworm has evolved in France since the marketing of griseofulvin was stopped in 2021, an antifungal which previously constituted the standard treatment.
Alternatives are now offered, including terbinafine and itraconazole. A working group coordinated by the Dermatology Evidence Center of the French Society of Dermatology has developed a treatment algorithm, updated in September 2026.
The choice of medication depends in particular on the fungus suspected or identified, the child’s weight and their ability to swallow the available oral forms. Terbinafine can, in certain situations, be prescribed even before the results of the sample are known.
Treatment generally combines an oral antifungal with local treatment, in the form of a cream or lotion. Local treatment alone is usually insufficient to clear the scalp infection.
These medications are generally well tolerated, but can cause adverse effects, particularly on the liver. The doctor therefore determines the necessary monitoring based on the child’s situation. For children weighing less than 10 kg, specialized hospital care is recommended.
Even if the lesions appear to be improving, it is important to respect the prescribed duration and to attend the planned clinical check-up at the end of treatment. If symptoms persist or worsen, the doctor can re-examine the diagnosis, check that the treatment is being taken correctly and look for possible resistance.
Healing therefore does not only depend on the medication chosen: it also requires appropriate monitoring and regular treatment.
The whole family should be screened, but not necessarily treated
When ringworm is diagnosed in a child, the question quickly arises: are other members of the family at risk of being infected? The recommendation is clear: all people living in the same household should be screened, but only those who are actually affected should be treated.
A few measures also make it possible to limit transmission. It is recommended to wash laundry that has been in contact with the head at 60°C and to disinfect hairdressing equipment. If a pet is likely to be the source of the infection, a veterinary examination is necessary.
To facilitate the application of the local treatment, it may be useful to cut short hair with scissors, without shaving it, or to undo the braids.
These precautions should not lead to guilt on the child or their loved ones. Ringworm is a transmissible infection: the main thing is to recognize it, treat it correctly and limit contamination.
Faced with a suspicious plaque, the right reflex therefore remains to consult, have the diagnosis confirmed by a sample and follow the treatment to the end. Appropriate care makes it possible to act both for the health of the child and to protect those around them.