Chicken pox (varicella)

Chicken pox (varicella)

1. CHICKEN POX (Varicella) Dr. Kuldeep Vaishnav Intern, NMCTH

2. INTRODUCTION Acute, Highly infectious disease caused by Varicella-zoster Virus. It is characterized By vesicular rash that may be accompanied by Fever and Malaise. It is worldwide in distribution and occurs in both epidemic and endemic forms.

3. INFECTIOUS AGENT Varicella Zoster Virus [Human (alpha)herpes 3) DNA virus, member of herpes. VZV only affects Human & Commonly causes Chicken pox in childrens , teen & Young adults, And Herpes Zoster (Shingles) In adults & rarely in children.

4. HOST FACTOR Man is host of Virus. Age under 10 years of age Immunity One Attack give life long immunity. Secondary attack rate- chicken pox is highly communicable. Secondary attack rate in household contact is up to 90%

5. Environmental Over crowding increases the chance of disease Show a seasonal trend- in temperate climate there is little evidence of seasonal trend Reservoir Infected persons are reservoir Source of infection Oropharyngeal secretion Lesion of skin & Mucosa Infectivity Ranges from 1-2 days before the appearance of rash & 4-5 days thereafter Infectivity ceases once lesion are crusted Virus tend to die out before pustular stage

6. Mode of transmission Direct Person to person through droplet or air borne spread Virus can cross the placenta Indirect Through articles freshly soiled by the discharge from the mucus membrane of the patient Incubation Period 14-16 days Susceptibility & Resistance It is universal among those not previous attacked

7. PATHOGENESIS 7

8. CLINICAL FEATURES May varies from a mild illness with only scattered lesion to severe febrile illness with widespread rash. Stages : Pre-eruptive stage Eruptive stage

9. PRE-ERUPTIVE STAGE Onset is sudden with mild or moderate fever, pain in back, shivering & malaise. Very brief stage lasting for 24 hours. In adults more severe & last for 2-3 days before rash comes out.

10. ERUPTIVE STAGE In children rash is the often the 1 st sign It comes on the day the fever starts Distribution of Rash:- Symmetrical rashes Centripetal in distribution A- 1 st appear on Trunk (Abundant) B- then face, arm & legs (Less abundant) Mucosal surface generally involved Axilla may be affected Palm & soles usually not affected Density of eruptions diminishes centrifugally

11. Rapid Evolution Macule→ papule → vesicles → pustule → scab Pleomorphism A characteristic features of the rash in chicken pox All stage of rash may be seen simultaneously at one time in same area This is due to appearing in successive crop for 4 to 5 days in same area Fever Does not run high but shows exacerbation with each fresh crop of eruption

12. DIAGNOSIS 12 Points for Diagnosis: Prodrome of low-grade fever Eruption of papules, vesicles and pustule Typical Dew-drop on Rose petal appearance Characteristic centripetal distribution

13. INVESTIGATION Investigations are rarely required. In doubtful cases Tzank -smear Done from floor of vesicles Floor of vesicles show of multinucleated giant cells.

14. DIFFERENTIAL DIAGNOSIS Vesicular exanthems Contact dermatitis Impetigo Insect bite Drug eruptions Small pox and other poxviruses 14

15. TREATMENT Mild Case ( chilldren ) Calamine lotion Antihistamines Severe case (Adults, HIV+) Acyclovir 800 mg, 5 times x 7-10 days Famciclovir 250 mg TDS x 10 days Other: Topical antibacterial Ointment like Mupirocin to prevent secondry bacterial infection Antipyretic

16. PREVNTION & CONTROL Control: Notification to the health authorities Isolation for 1 week Contact with susceptible patient is avoided Disinfection of articles soiled by nose an throat discharge Prevention: Live attenuated vaccine in susceptible patients hyperimmunoglobulin

17. COMPLICATIONS In most cases, chicken pox a mild, self-limiting disease. The mortality is less than 1 % in uncomplicated cases. Varicella Hemorrhage Pneumonia Encephalitis Acute cerebellar ataxia Reye’s syndrome Fetal death and Birth defects

18. HERPES ZOSTER (SHINGLES) Etiology Varicella zoster virus, after an attack of chicken pox, virus lies dormant in secondary root ganglia. Zoster in manifestation of its reactivation Predisposing factor Old age Lymphoreticular malignancy HIV infection Sometimes without apparent cause 18

19. Clinical Features Prodrome of segmental pain (usually excruciating !) begins 1-4 days before eruption Morphology Very painful, segmental eruption of grouped papules & Vesicles on an erythematous, slightly edematous base. Self limiting Crust & heal in about 2 wks in absence of immunocompromised patients Site of Predilection Uni / multidermatomal . Thoracic intercostal nerves & ophthalmic division of trigeminal nerve 19

20. Treatment Symptomatic treatment with analgesics Specific treatment with antiviral (Acyclovir, Famiciclovir & Valacyclovir ) Severe zoster Ophthalmic zoster Immunocompromised patient Elderly (to reduced postherpetic neuralgia) Complication Postherpectic Neuralgia Facial palsy, secondary infection & generalization 20

21. REFERENCE Dermatology and Sexually Transmitted Diseases- Neena Khanna Dermatology in general medicine- Fitzpatrick’s Park’s textbook of Preventive and social Medicine- K. Park Medscape Internet

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