Dengue: Causes, Signs and Symptoms. Diagnosis, Stages, Treatment

Dengue is derived from the African word “Denga” which means fever with haemorrhage. And what are those 9 things about dengue disease everyone should know?


It is spread by the Female mosquito AEDES AEGYPTI which sucks blood from the infected body and during sucking her meal, she sucks DENGUE VIRUS. The disease is considered mostly in the monsoon or rainy season when mosquitoes have an easy supply of stagnant water to reproduce.

Mosquito- Aedes Aegypti, Virus- DENV (Dengue virus)
Mosquito- Aedes Aegypti, Virus- DENV (Dengue virus)

Dengue virus or DENV is an RNA virus of five serotypes- DENV-1, DENV-2, DENV-3, DENV-4 and DENV-5 (DENV-5 announced in 2013).

Sign and Symptoms

Most affected people are without any symptoms or mild fever. Children are most susceptible to dengue and develop life-threatening conditions. This is the most important part. The earlier you suspect you have it, the better the result from treatment. Note that a rash is not typical of dengue.

Dengue fever triad = Fever + Rash + Headache

It should be immediately suspected if you have:-

Fever (40°C/104F) 

with any 2 of the following:

  • Severe headache
  • Pain behind eyes
  • Muscle and joint pain
  • Vomiting
  • Tiredness
  • Black stool
  • Nose or gum bleeding 

These symptoms will start within a few hours of a mosquito bite and last for up to 14 days.

What not to do?

It reduces your platelet count and causes dehydration. The following things should be AVOIDED in all cases:-

  • Taking Aspirin or Disprin
  • Taking any antibiotic
  • Taking any NSAID for pain and fever

(These are contraindicated as these cause further platelet damage and worsens it.)

  • Getting dehydrated- As the fever warms up the body and causes blood loss from the body, there are chances of several dehydration. One should always try to keep him hydrated with drinks.
  • Ignoring symptoms and avoiding visits to a physician- The earlier you know, the better you survive.

Clinical diagnosis

Once you reach the physician, he will immediately order the following tests:-

  • Complete blood test (CBC)
  • X-ray Chest (CXR)
  • Plasma thromboplastin time and prothrombin time

Why all these tests? These tests reveal the following to the physician:-

>Complete blood test- Reveal marked reduction in platelet count (<100,00/cubic mm) called Thrombocytopenia. Also, reveal Haemoconcentration.

>X-ray chest- This reveals pleural effusion in the lung, mostly on the right side. Bilateral (both-sided) pleural effusion occurs in very severe cases of Dengue Shock Syndrome.

>Plasma thromboplastin time and prothrombin time- These are prolonged and thus mean prolonged bleeding time.

The lab diagnosis, though, differs from the clinical diagnosis. The approach is highly specific.

Lab diagnosis

The most specific tests for Dengue fever include:-

  • ELISA- MAC-ELISA is done
  • IgM/IgG ratio- It is increased
  • Haemagglutination inhibition test- it reveals 4 fold rise in antibody response
  • Other tests- Include Neutralization tests like serum dilution, virus constant,plaque-reduction test, Dot-blot immunoassay and Complement fixation test (CFT).


Dengue is caused by a virus, hence, no specific management is available till now (not even anti-viral drugs). However, only symptomatic treatment is done.

The symptomatic treatment of involves:

Management of pain and fever

Paracetamol is the only drug of choice for dengue. However, doses guidelines as per WHO are as follows:-

1 year 60 mg/dose
1–3 years 60–120 mg/dose
3–6 years 120 mg/dose
6–12 years 240 mg/dose

A dose should be administered when body temperature is greater than 39°C, but no more than 6 doses should be administered in a 24-hour period.

Maintaining Fluid levels

This is done by IV fluids to prevent the patient from going into the shock stage.

A dose should be administered when body temperature is greater than 39°C, but no more than 6 doses should be administered in a 24-hour period.

Administration of I.V. (intravenous fluid) is necessary as the patient has a >20% increase in haematocrit and early signs of circulatory disturbance (i.e. rapid pulse and worsening condition).


It becomes the only solution when-

  • Cool, mottled or pale skin
  • Reduced peripheral pulses
  • Changes in mental status
  • Increased heartbeat (Tachycardia)
  • Increased capillary refill time (.2s)
  • Oliguria
  • Sudden rise in haematocrit or continuously elevated haematocrit despite administration of fluids
  • Narrowing of pulse pressure (<20 mmHg (2.7 kPa) )
  • Hypotension (a late finding representing uncorrected shock)


Dengue is presents in three stages from the time of biting by a mosquito, i.e., entry of the virus into the human body. These stages are:

Dengue Stages Manifestation
Stages of Dengue and Manifestations

Symptomatic stage (Febrile stage)

This is where the fever and other symptoms start. It peaks and remains for 2-7 days.

Dengue hemorrhagic fever (Critical stage)

Fever comes down to normal body temperature. The plasma from the blood capillaries starts leaking. This results in fluid accumulation in the chest (pleural effusion) and abdominal cavity (ascites) while decreasing blood supply to vitals. Cutaneous and intestinal haemorrhages are features of DHF.

Dengue shock syndrome (DSS)

This is the most serious manifestation of dengue and results in untreated patients or vulnerable children. This is the cause of death.

Noting point is, in most people, it is less serious as:

  • Stage A can occur without symptoms (asymptomatic).
  • Stage B can occur as Dengue Fever (DF) Syndrome which is a self-limiting febrile illness affecting muscles and joints with severe back pain due to myalgia (hence the name ‘break-bone’ fever).


The cause of death is the end stage, Dengue Shock Syndrome (DSS) which is characterised by:

  • Bluish colouration of the skin
  • Cold, clammy skin and restlessness
  • Rapid and weak pulse
  • Narrow pulse pressure
  • Hypotension

The patient starts feeling lethargy, which follows by shock and coma and finally, death in untreated patients.


The last and tricky question that comes is- CAN I HAVE DENGUE AGAIN?

The answer to the question is YES. Since it has 5 serotypes, any other can affect you even if you have been affected. Moreover, the condition is more serious if this happens. This is called Secondary infection.

Dengue is always a hot topic during monsoon season, and you don’t want to miss out on such an important endemic around you.  Hope we helped you. Feel free to share the page. Any doubts or suggestions or feedback is always welcome.


Related Articles


Please enter your comment!
Please enter your name here