Chickenpox or Varicella
Chickenpox or Varicella is a highly contagious disease caused by varicella zoster virus (VZV) a member of herpes zoster family which appears to be due to reactivation of a latent infection with chicken pox virus. The disease usually begins with vesicular skin rash mainly on the head and body rather than at the periphery which becomes itchy, raw pock marks and often heals without scar marks. On examination lesions of chicken pox are seen at various stages of healing.
Chicken pox is highly infectious and mainly affects children under 10 years of age. Adults may develop a more severe illness including a prodromal rash.
Incubation Period of Chicken pox or Varicella
Incubation period of chickenpox is 10 to20 days. A child with chickenpox is restricted to return to school or play with other children till all sores have crusted over or dried out.
Adults also follow this rule when, when to return to work or be around others.
Causes of chickenpox
The causative organism of chicken pox is Varicella Zoster Virus (VZV), a member of Herpes Zoster virus family. Herpes zoster (Shingles) appears to be due to reactivation of the latent infection with chicken pox virus in adults.
Mode of spread of chickenpox
Chickenpox is highly infectious airborne disease and can be spread very easily to others through:
• Droplets from upper respiratory tract if someone with the disease coughs or sneezes near you.
• Contamination from the discharge from ruptured lesions of the skin.
• Through contact with a patient with herpes zoster.
• One may get chicken pox even from touching the fluids from the chickenpox blister.
• A patient of chickenpox is contagious 1-2 days before the appearance of blisters and remains contagious until all the blisters are crusted over.
• Crusted lesions are not contagious.
Risk factors of chickenpox
• Children between 4 to 10 years of age are mostly at risk.
• Chicken pox infection can pass in developing baby when it occurs in pregnant woman. Newborns are at risk for severe infection.
• Severe chicken pox symptoms are more common in children whose immune system is poor due to an illness or medicines like steroids and chemotherapy.
• Children whose mothers previously have chickenpox, or vaccinated against chickenpox are not very likely to catch it before the age of I year. If they do so, they often have mild infections. This is because antibodies from their mother's blood which protect them.
• Children under 1 year whose mother have not had chickenpox or vaccinated against chickenpox can get severe chickenpox.
Clinical features of chickenpox
The onset of disease is usually characterised by symptoms:
• Muscle pain
• Fever (100 degree,& may rise upto106 degree centigrade)
• Sore throat
• Pain in both ears
• Rarely severe backache &
• Loss of appetite
• Chickenpox is more severe in adults and rarely fatal.
• Constitutional symptoms are usually brief & mild and the first sign of disease is often rash.
• Lesions are sometimes present on the palate before the characteristic rash appears on the trunk on the 2nd day of the illness. Then the face and finally the limbs are involved.
• The rashes reach their maximum density upon the trunk and are sparser on the periphery of the limbs. Then the face and finally the limbs are involved.
• Axillae are inspected with positive rashes while in case of small pox rashes are –ve (axillae involved in chicken pox).
• Maculae appear first and within a few hours the lesions become popular and vesicular.
• The vesicles are unilocular, very superficial, thin-walled &surrounded by a wide zone of erythema with elliptical shape.
• The lesions become pustule within 24 hours.
• The vesicles and pustules are so fragile that they may be ruptured by the changing of garments.
• Damage from scratching is also frequent, since itching may be troublesome especially in children.
• Whether or not the pustules rupture, they dry up in a few days to form scabs.
• The spots appear in crops, so that lesions at all stages of development are seen in any area at the same time.
• The course of the disease is usually uneventful.
Complications of chickenpox
Complications of chickenpox are as follows:
• Secondary infection of the lesions in the mouth and skin by staphylococci & streptococci.
• Encephalomyelitis may occur
• Chickenpox pneumonia may occur in neonates or adults which is very serious illness.
• Serious complications can occur in patients of AIDS, Leukaemia, Lupus, Cancer, and in people taking immune suppressing drugs (like cortisone).
• Transient Arthritis
• Cerebellar ataxia may occur during or later
• Infection can pass in developing baby when it occurs in pregnant woman. Newborns are at risk for severe infection.
Diagnosis of chickenpox
• Typical case of chicken pox presents no diagnostic problem.
• It is important to remember that great difficulty may be encountered in cases of modified smallpox and variola minor.
• The diagnosis of chickenpox is primarily clinical with early symptoms (prodromal) and the characteristic rash. Diagnosis is confirmed by examinati-on of the fluid within the vesicles of the rash or by testing blood of acute imm-unologic response.
Epidemiology of chickenpox
• The disease occurs in endemic form to all countries worldwide.
• The chickenpox virus (varicella zoster virus) has widespread prevalence that is stable from generation to generation.
• In countries with temperate climate, chickenpox is usually a disease of childhood. The disease mostly occurs during the winter and spring seasons.
• Chickenpox is one of the classic diseases of childhood, with the high incidence between the age group of 4 to 10 years. Chicken pox is highly com-municable disease, with an infection rate up to 90% in close contacts.
• Like rubella, chickenpox is also uncommon in preschool children.
• In temperate countries, usually most of the people get infected before adulth-ood though about 10% of young adults remain susceptible.
• In tropical countries, chickenpox often occurs in older people and can cause more serious disease.
• In adults the pox marks are darker and the scars are more prominent than in children.
Prevention of chickenpox
Chickenpox is prevented by:
• Hygienic measures
Hygienic measures are as follows:
• Chickenpox can be prevented by isolation of patient, because contagion is by exposu-re to droplets by sneezing and cough or
• Direct contact with lesions within a period from 2-3 days prior to the onset of the rash to 4 days after the onset of the rash.
• Chickenpox virus is susceptible to disinfectants like chlorine bleach (sodium hypo chloride)
• Like all enveloped viruses, chickenpox virus is sensitive to desiccation, heat and detergents.
Vaccination for Chicken pox or Varicella
Chickenpox is prevented by chickenpox vaccine which usually prevents the disease or makes the illness very mild.
Treatment of chickenpox
• Like other viral infections, there is no specific treatment of chickenpox. No treatment is required in majority of the cases.
• Itching may be relieved by an antihistamine drug taken orally.
• At the first sign of secondary infection a local antiseptic should be applied to the skin.
• If bacterial infection progresses, an appropriate antibiotic should be prescribed.
• Precautionary measures are performed to keep the person comfortable.
• Avoid rubbing or scratching the itchy lesion areas.
• Keep finger nails short to avoid damaging the skin by scratching.
• Wear light, loose, cool bedclothes.
• Avoid wearing rough clothing, especially wool, over an itchy area.
• Take lukewarm baths using little soap and rinse thoroughly.
• Apply a soothing moisturizer after bathing to soften and cool the skin.
• Avoid prolonged exposure to excessive heat and humidity.
CONTRAINDICATION: Aspirin or Ibuprofen is contraindicated in chickenpox. Use of aspirin has been associated with a serious condition called Reves syndrome. Ibuprofen has been associated with more severe secondary infections.
Acetaminophen/ Paracetamol may be used.
Prognosis of chickenpox
Prognosis of chickenpox is good. Usually a patient of chickenpox recovers without any complications.Once a person has had chickenpox, the virus often remains dormant or asleep in the body for lifetime. About 1 in 10 adults will have herpes zoster when the virus re-eme-rges during a period of stress.