How does the disease progress?
The infection develops in two stages. A week and a half after infection, nonspecific complaints appear: slight fever, runny nose, headache, aches. It is during this period that a person is contagious to others. Then the state of health improves, and after a few days a rash appears: first, merging redness on the cheeks with a pale nasolabial triangle, then mesh pink spots on the shoulders, hips and torso. The rash may fade and reappear within a few weeks after a hot bath, exercise, or sun exposure.
- Incubation period is approximately 1–2 weeks
- The first phase is similar to a mild ARVI
- Contagiousness occurs in the period before the rash
- Red cheeks are a classic sign in children.
- Lacy rash on the limbs and torso
- The rash returns in waves with heat and exertion
Features in adults
In adolescents and adults, especially women, the rash is mild or absent, but joint manifestations are pronounced. The small joints of the hands, wrists, knees and ankles become inflamed symmetrically: pain, stiffness, and sometimes swelling appear. This condition resembles the onset of rheumatoid arthritis, but, unlike it, it goes away on its own in a few weeks, rarely in months, and does not destroy the joints. Therefore, when symmetrical arthritis occurs for the first time, the doctor clarifies whether there was any contact with a sick child.
- The rash in adults is often erased
- Symmetrical pain in small joints of hands and feet
- Morning stiffness
- Goes away on its own without destroying the joint
- Requires differentiation from rheumatoid arthritis
Why is parvovirus B19 dangerous?
The virus temporarily stops the formation of red blood cells. In a healthy person this is unnoticeable, but in people with constant accelerated breakdown of red blood cells - with sickle cell anemia, thalassemia, hereditary spherocytosis - an aplastic crisis develops with a sharp drop in hemoglobin, pallor, weakness and shortness of breath. This condition requires hospitalization. When a pregnant woman is infected, the virus can penetrate to the fetus and cause severe anemia and dropsy, most often when infected in the first half of pregnancy. In people with reduced immunity, the infection can take a protracted course with persistent anemia.
- Aplastic crisis in chronic hemolytic anemia
- Anemia and hydrops of the fetus when a pregnant woman is infected
- Prolonged anemia in immunodeficiency
- In healthy children the course is benign
- People usually don’t get sick again - they remain immune
Diagnostics
In a typical case, a child is diagnosed during examination: the characteristic cheeks and lacy rash after a mild illness are sufficiently recognizable, and tests are not needed. The examination is required in special situations. When a pregnant woman comes into contact with a patient, IgM and IgG antibodies are determined: the presence of only IgG indicates a previous infection and protection, IgM indicates a fresh infection. For anemia, a complete blood count and reticulocyte count are performed; for immunodeficiency, PCR is used to detect viral DNA. The doctor also rules out measles, rubella and scarlet fever.
- Examination and assessment of the nature of the rash
- IgM and IgG antibodies to parvovirus B19
- Complete blood count and reticulocyte count for pallor
- Blood PCR for immunodeficiency
- Differentiation from measles, rubella, scarlet fever, allergies
Treatment and prevention
Antiviral treatment does not exist and is not required: in healthy children the disease goes away on its own. You need a normal regimen, sufficient fluids and antipyretics at high temperatures. Antibiotics are useless because the causative agent is a virus. The rash is not contagious and does not require ointments; the itching is relieved by a cool shower and light clothing. For adults with joint pain, the doctor may prescribe anti-inflammatory drugs. There is no vaccination against parvovirus B19, so prevention comes down to hand hygiene and limiting contact with sick people for pregnant women and patients with blood diseases.
- Drink plenty of fluids and rest
- Antipyretic for fever and feeling unwell
- No antibiotics needed
- There is no need to isolate the child after the rash appears.
- Pregnant women - avoid contact and discuss tests with your doctor
- For chronic anemia, consult a doctor immediately
- Regular hand washing reduces transmission