Fifth Disease

Causative agent

Fifth disease is a rash illness caused by parvovirus B19. This virus infects humans only.

Clinical features

Fifth disease is a mild rash illness that occurs more commonly in children. A typical rash occurs on the face, giving the 'slapped-cheek' appearance. It may appear less commonly on other parts of the body such as limbs and trunk. The rash may be itchy and usually disappears in 7 - 10 days. Low-grade fever and tiredness often precedes the appearance of the rash.

In adults, the disease is even milder and may present as joint pain and swelling only.

A pregnant woman with parvovirus B19 infection can pass the virus to her baby, and may cause foetal death. It can also lead to severe anaemia in patients with low immunity (e.g. AIDS and leukaemia).

Mode of transmission

Parvovirus B19 is transmitted primarily through direct contact with respiratory secretions of infected patients. It can also be transmitted from mother to foetus during pregnancy, and through blood or blood products.

Incubation period

Incubation period is 4 - 20 days.

Management

Fifth disease is usually a mild illness. No definite treatment is needed. Treatment usually involves relieving symptoms such as fever, itching, joint pain and swelling. Patients should rest at home until they fully recover.

Pregnant women, women preparing for pregnancy and other high-risk individuals who have close contact with patients of parvovirus B19 infection should consult doctor for further management.

Prevention

• Perform hand hygiene frequently, especially before touching the mouth, nose or eyes; after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretion after coughing or sneezing.
• Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
• Cover your mouth and nose with tissue paper when sneezing or coughing. Dispose the soiled tissues into a lidded rubbish bin, then wash hands thoroughly.
• When having respiratory symptoms, wear a surgical mask, refrain from work or school, avoid going to crowded places and seek medical advice promptly.
• Avoid close contact with patients who have fifth disease.

• Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 – 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Maintain good indoor ventilation. Avoid going to crowded or poorly ventilated public places; high-risk individuals may consider putting on surgical masks while in such places.