More Dengue information from the Health Protection Surveillance Centre

Dengue Rash is typically faint, erythematous and macular


  • Incubation period 3-14 days (usually 4-7)
  • Abrupt onset fever, chills, headache, arthralgia
  • Back pain ("breakbone fever") and prostration ( exhaustion)
  • Rash in 50% - faint macular, erythematous with discrete pale spared areas
  • Capillary test confirms capillary fragility
  • Lasts up to 10 day
  • May progress to haemorrhagic fever (beware petechial rash fragile gums) and shock (may be fatal)
  • No vaccine available
  • Prevention - avoid mosquito bites (advice)
  • Severe 'flu like viral infection, all age groups
  • Transmitted by Aedes mosquito bite
  • Bites risk : daytime, tropics & subtropics
  • Recently Comoro Islands.

Capillary test

Specificity >85%, sensitivity 30%

Apply BP cuff above venous pressure for 5 minutes. Positive = >2 petechiae distal to the cuff.


  • Leucopenia with a relative lymphocytosis
  • Thrombocytopenia
  • Abnormal LFTs
  • Clotting abnormalities if haemorrhagic / shock developing
  • Confirm Dx with IgM antibodies against flavivirus


  • Supportive

Differential Dx

  • Malaria - ALL need malaria screens
  • Rickettsial infections
  • Enteric fever
  • Acute HIV seroconversion

Advice for travellers

Time: Precautions during daylight

Avoid risky areas: i.e. near water

Use mosquito repellents:

Dress safely: wear long sleeves, long trousers, socks and closed shoes.

Use air conditioning and screens

More information (WHO)

Content From the HPSC site by Dr Íomhar O' Sullivan 26/03/2010. Last review 10/06/21.