Chicken pox

Chickenpox is an infection caused by the varicella-zoster virus usually occuring in childhood ages. However, it can affect adults which holds the risk of more severe symptoms such as neurological complications (herpes zoster). The infection can impact any part of the body.

Epidemiology

Studies found that more than 90% of cases occurs in children younger than 10 years
Since the introduction of the varicella vaccine, the incidence of the condition has reduced up to 90%
Tropical and semi-tropical climates in countries have a higher risk of incidence of adult chickenpox than temperate climates eg. UK. [1]
According to a study found in Vaccine, almost all children will experience chickenpox during the first 5 years of life [2]
Children usually likely to have chickenpox in winter and spring [3]

Chickenpox

White pustules that can affects the soft palate of the inside of the mouth.

Can also cause small sores in the mouth as well as blisters and scabbing on the skin

Pathophysiology [1]

Medical Student
- The virus first infect the conjunctivae or the mucosa of the upper respiratory tract.
- This causes viral proliferation in the regional lymph nodes post initial infection (2-4 days), viremia (virus in bloodstream) occurs 4-6 days post infection
- The secondary round of viral multiplication is found in the organs, most prominently the spleen and the liver. This causes the viral infection to invade the capillary endothelial cells and epidermis.
- Leading to the infection invading the malpighian layer (layers of the skin where cells are continuously dividing)
- This produces inter (between) and intra (within) cellular oedema; which creates the typical presentation of vesicles
- Exposure to the virus triggers the immunoglobulins- A,G,M antibodies to stay within the body for life and maintain immunity to the virus.
- In cases of secondary infection to chickenpox (varicella)- the virus is assumed to spread from the mucosal and epidermal sites to the local sensory nerves.
- This can account for the neurological symptoms that may occur in secondary infections.
- The virus remains latent (inactive) in the cells (dorsal ganglion) of the sensory nerves
- Reactivation of the virus causes the clinical condition of herpes zoster (shingles) which holds a lot of clinical manifestations
Patients
- The virus first infect the eyes or the upper respiratory tract (including the nose, nasal cavity, mouth, throat and voice box)
- This causes the virus to grow and spread to the lymph nodes in the body after the initial infection (2-4 days), viremia (virus in bloodstream) occurs 4-6 days post infection
- The second stage of virus development includes affecting the organs, most prominently the spleen and the liver. This causes the viral infection to invade cells in the bloods vessel (capillary) and skin
- Leading to the infection invading the layer of the skin where cells are continuously dividing
- This produces swelling of the cells between each other and within the cells; which creates the typical presentation of vesicles
- Exposure to the virus triggers a group of proteins present in the cells and fluid of the immune system to stay for life in the body and maintain immunity to the virus.
- In cases of secondary infection to chickenpox (varicella)- the virus is assumed to spread from the skin to the sensory nerves.
- This can account for the neurological symptoms that may occur in secondary infections.
- The virus remains inactive in the cells of the sensory nerves
- Reactivation of the virus causes the clinical condition of herpes zoster (shingles) which holds a lot of extra symptoms

Source: NHS

Chickenpox
Close up image of stage 2 chickenpox

Source: NHS

Chickenpox
Dark skin with stage 2 chickenpox

Causes [4]

Usually from the airborne respiratory droplets from an infected host who carried the varicella zoster virus

Risk factors [4]
- Immunocompromised people (no evidence of immunity to varicella virus)
- Newborns with mothers who had varicella 5 days before or 2 day after delivery
- People with HIV or AIDS
- Pregnancy women without immunity to the varicella virus
Presentations [5]
- Headache
- Fever
- Malaise (sickness)
- Flushing of the skin
- Rash in early stages
- Itchy spots with redness
- Crop (clustered) pattern of spots
- Crusting of the spots
- Severe cases include the trunk, extremities, or face
- Ulcering of the spots (lesions)
Investigations

Clinical examination from presentations but may not be conclusive
History taking including recent exposure to chickenpox, risk factors, typical features of chickenpox and symptoms associated with chickenpox complications.
Polymerase Chain Reaction testing for the varicella virus; taken from the scabs, fluids from the spot and scrapings [6,7]

Chickenpox

Blisters look like ‘dew drops on a rose petal’ due to the clear drops on pink discolouration

Differential diagnosis [6]
- Other viral infections that present with vesicles (spots):
  - Herpes simplex (STD)
  - Herpes zoster (shingles)
  - Coxsakie virus- Hand, foot and mouth disease
- Infections:
  - Impetigo
  - Scabies
  - Syphilis (STD)
  - Meningitis
  - Toxic shock syndrome- medical emergency caused by bacteria
- Skin disorders:
  - Drug eruption
  - Insect bites
  - Erythema multiforme- reaction to allergies
  - Guttate psoriasis- skin disorders presented with small, teardrop spots caused by the streptococcal infection
  - Papular urticaria- reaction to allergies presented with papules (skin lesions)

Management [7]

Medical Student
- In mild cases of chickenpox, advise symptomatic treatment. This includes;
  - A Wet compress to reduce itching and fever
  - Anti-histamines to alleviate hay fever and other symptoms)
  - Oatmeal baths for severe itching
  - Keeping the underclothing clean and keep the nails clipped
  - School or work should be not be attended until the final lesions have crusted over.
- Prescribe oral antivirals to healthy people who are at risk of experienceing a moderate-severe disease, drugs include;
  - Valacylovir
  - Famciclovir
  - Acylovir
- Consider prescribing antipyretics (reduces fever) such as;
  - Acetaminophen
Patients
- In mild cases of chickenpox, advise treatment which manages the symptoms of chickenpox (including fever, itching etc). This includes;
  - A Wet compress to reduce itching and fever
  - Anti-histamines to alleviate hay fever and other symptoms)
  - Oatmeal baths for severe itching
  - Keeping the underclothing clean and keep the nails clipped
  - School or work should be not be attended until the final lesions have crusted over.
- Drug treatment for the virus are called anti-virals and they include;
  - Valacylovir
  - Famciclovir
  - Acylovir
- Consider prescribing antipyretics (reduces fever) such as;
  - Acetaminophen
Prevention [7]
- Chickenpox vaccine is provided if the risk of spreading the virus to people who cannot respond to an infection adequately (immune suppressed) (eg. a child can be vaccinated with 1 parent who is undergoing chemotherapy)

Complications [4]
- Herpes zoster is the reactivated version of varicella zoster (occurs after a latent/ non expressive period of the varicella zoster)
- Bacterial infections in children
- Viral pneumonia in adults- respiratory infection
- Cerebella ataxia- brain impacted, causing difficulties in co-ordination, balance and speech
- Encephalitis- blain becomes inflammed
- Septicemia- blood infection
- Toxic shock syndrome- medical emergency caused by bacteria
- Necrotizing fasciitis- rare bacterial infection caused by group A streptococcus
- Osteomyelitis- infection of the long bones in the body
- Septic arthritis- infection of the joints
- Bleeding problems (hemorrhagic)

Source: NHS

Chickenpox
Light brown skin with stage 2 chickenpox spots

Source: NHS

Chickenpox
Stage 1 chickenpox spots in light brown skin

Myths
- Chickenpox isn’t serious
- Chickenpox only affects children
- Vaccines are less effective than exposure to chickenpox
- Vaccines cause chickenpox
- Chickenpox can only be achieved through direct contact
- All children should be exposed to the virus as soon as possible
- Vaccine provides 100% protection against chickenpox [8,9]

Questions you may want to ask your doctor
- How do I know if I had chickenpox as a child? How can I check?
- What protection can be provided for people with immune complications?
- How can I contact for support if I have been in contact with chickenpox and I am pregnant?
- How do I know what chickenpox stage of development I am on?
- How does chickenpox spread?
- What are the side effect of the chickenpox vaccine?
- Why should my child get the vaccine rather than build up natural immunity through exposure? [10,11]
Support
- Chickenpox aware
- American Academy of Dermatology
- Bupa