Brief overview
- Course and prognosis: Mostly good; severe course possible in pregnant women and people with weakened immune system
- Causes and risk factors: Parvovirus B19
- Symptoms: Often none, otherwise: bright red skin rash, flu-like symptoms, in children possibly itching, in young women joint pain
- Diagnosis: Recognition of the typical skin rash, blood test, bone marrow sample if necessary
- Prevention:Hand hygiene, no vaccination
What is ringworm?
Ringworm is a disease caused by infection with parvovirus B19.
Ringworm: Infection and incubation period
Between infection and the appearance of the first symptoms, usually just under two weeks pass. This period is called the incubation period.
Affected persons are infectious in the initial stage, i.e. a few days after infection and before a rash possibly appears. There is virtually no risk of infection once the rash develops.
After a ringworm infection, affected persons have lifelong immunity to the disease.
Ringworm is not notifiable in Germany, Austria or Switzerland.
What is the course of ringworm in children?
Following a ringworm infection, the skin, especially on the face, is often very scaly and requires increased skin care for about four weeks.
What is the course of ringworm in adults?
Like other childhood diseases, ringworm carries the risk of causing unusually severe symptoms in adulthood and being severe. It is especially dangerous for pregnant women and people with weakened immune systems.
What is the course of ringworm in adolescents?
What is the course of ringworm in pregnancy?
Two-thirds of women of childbearing age are immune to the ringworm pathogen. If this is not the case, caution is advised, because if a pregnant woman becomes infected with ringworm, this may have serious consequences for the unborn child.
If ringworm is suspected during pregnancy, the child is therefore closely monitored by ultrasound. This makes it possible to take appropriate countermeasures at the first signs of reduced blood volume in the baby.
Learn more about the risks and treatment of ringworm during pregnancy in the article Ringworm – Pregnancy.
What are the symptoms of ringworm?
Ringworm symptom: skin rash.
The garland- or ring-shaped rash (“infantile rash” as it is called) is a characteristic symptom of ringworm. However, it occurs in only about one in four patients. It is presumably not triggered directly by the ringworm virus, but arises due to the body’s own immune reaction against the pathogen.
After a few days, the rash fades. Occasionally, it flares up again and again over a period of one to two months. This may be caused by exposure to sunlight or high temperatures, for example when bathing.
Ringworm, along with measles, rubella, chickenpox and scarlet fever, is one of the five childhood diseases that frequently cause a rash. In English-speaking countries, they are therefore also called “Fifth disease”.
Ringworm symptom: anemia
- Tiredness and fatigue
- Paleness of the skin: blood is responsible for a healthy skin color; therefore, in anemia, patients often appear pale.
- Increased pulse: To ensure that the body’s cells still receive enough oxygen despite anemia, the heart begins to pump blood faster through the circulatory system.
Dangers from the ringworm virus
Ringworm infection in girls and women occasionally leads to polyarthritis, an inflammation in several joints. Knee, ankle and finger joints are particularly often affected. These inflammations are an erroneous reaction of the immune system, but they usually pass on their own and do not require special treatment.
What causes ringworm?
Parvovirus B19 recognizes a very specific surface structure of erythroblasts (precursors of red blood cells) and invades these cells. Some people lack this characteristic structure on their blood cells. They are therefore immune to the parvovirus from birth.
How is ringworm diagnosed?
The doctor usually diagnoses ringworm on the basis of the typical skin rash. In the case of unclear symptoms or in patients without a skin rash, a blood test confirms the diagnosis: either antibodies against the ringworm virus or the virus itself can be detected in the blood of infected persons.
Only in rare cases does the physician have to take a bone marrow sample (bone marrow puncture). If the patient actually has ringworm, parvovirus B19 can be detected in the sample.
How is ringworm treated?
Doctors often prescribe medications for fever and pain for this purpose. Cold compresses relieve the itching that occasionally accompanies the ringworm rash. In cases of severe anemia, a blood transfusion may be necessary.
How can ringworm be prevented?
There is no vaccine against parvovirus B19. The only measures to prevent infection are to maintain good hand hygiene and avoid contact with infected people. These measures are especially important for pregnant women. They are also better off avoiding entering a kindergarten or school if there has been an outbreak of ringworm there.
