Viruses are obligatory intracellular parasites. The mode of transmission of these viruses varies from respiratory to faeco-oral route, arthropod borne, venereal and penetrating wound.

CHICKEN POX/ VARICELLA

An infectious viral disease caused by varicella zoster virus. Transmission mainly by droplet. 90% cases occur in children and teenagers.

Clinical feature

•        Incubation Period: 4 -15 days.

•        Rash often preceded by 2 -3 days of prodromal symptoms- fever, chills, malaise, headache, anorexia.

•        Rash is polymorphic and is characterized by erythematous papules, vesicles “dew drops on rose petal”, umbilicated pustules. Arranged in centripetal manner mainly over the trunk and proximal limbs.

Diagnosis & Investigations

•        Mainly clinical diagnosis,

•        Tzanck smear from blister – shows multinucleated giant cells.

Non-pharmacological Treatment

•        Rest, cold compresses, tepid bath

•        The patient to be kept in isolation.

Pharmacological Treatment

•        Tab Acyclovir 800mg 5 times daily for 7 days (20mg/kg QID in children).

•        Tab Valacyclovir 1gm TID for 7 days

•        Tab Famciclovir 500mg TID for 7days

HERPES ZOSTER (SYN: SHINGLES)

It is a localized disease caused by reactivation of Varicella Zoster Virus lying dormant in the sensory ganglia.

Clinical features

•        Rash appears following prodromol symptoms like fever, malaise, paraesthesia.

•        Mostly unilateral, dermatomal and does not cross midline.

•        Closely grouped vesicles, papules and pustules.

•          Most common in thoracic region.

•        Most common complication is Post herpetic neuralgia.

Diagnosis & Investigations

•        Mainly clinical diagnosis.

•        Tzanck smear – shows multinucleated giant cells.

Non-pharmacological Treatment

•        Rest, cold compresses, tepid bath

•        The patient to be kept in isolation.

Pharmacological Treatment

•        Tab Acyclovir 800mg 5 times daily for 7 days (20mg/kg QID in children).

•        Tab Valacyclovir 1gm TID for 7 days

•        Tab Famciclovir 500mg TID for 7days

•        Therapy to be continued for 7 days in immune competent persons and for 14 days in immuno suppressed individuals.

•        Topical – Calamine lotion

•        Non-steroidal anti-inflammatory drugs – for pain

•        For post-herpetic neuralgia – amitriptyline, carbamazepine, phenytoin, gabapentin and pregabalin may be given.

HERPES LABIALIS

It is an infection of the lips by herpes simplex virus (HSV-1). It spread by close personal contact.

Clinical features

•        Incubation Period: - 5-7 days.

•        Mild prodrome of malaise and tingling sensation.

•        Closely grouped vesicles seen around lips.

•        Vesicles rupture to form shallow ulcers.

Diagnosis & Investigations

•        Mainly clinical diagnosis.

•        Tzanck smear- for multinucleated giant cell.

•        IgG, IgM HSV 1 and 2 antibodies.

Non-pharmacological Treatment

•        The patient should avoid contact until all the lesions are crusted.

Pharmacological Treatment

•        Tab Acyclovir 400mg 3 times daily for 5 -7 days.

•        Tab Valacyclovir 1gm bID for 7 days

•        Tab Famciclovir 250mg TID for 7days

MOLLUSCUM CONTAGIOSUM

An infectious disease caused by pox virus, Molluscum contagiosum virus. Commonly seen in children.

Clinical features

•        Incubation Period: 2 weeks-6 months.

•        Dome shaped, pearly white, umbilicated waxy papules.

•        Common sites - Children - axilla, side of trunk, lower abdomen, face. Young adults - genitalia

Diagnosis & Investigations

•        Mostly clinical diagnosis.

•        Giemsa stain – of expressed material to demonstrate HP bodies

•        Skin biopsy – to show molluscum body.

Non-pharmacological Treatment

•        Avoid scratching.

•        Avoid sharing of towels, contact sports and communal bathing.

Pharmacological Treatment

•        Chemical cauterization – by trichloroacetic acid 10-30%, phenol or salicylic acid. 10% potassium hydroxide in children.

•        Cryotherapy using liquid nitrogen.

•        Curettage or diathermy.

•        Cidofovir 1-3% cream in immunocompromised patients.

WARTS

An infection of skin and contiguous mucous membrane by different groups of Human papilloma viruses.

Clinical Features

•        Incubation Period - 3 weeks to 8 months.

•        Common Sites: back of hands, palms, finger, knees, soles, anogenital area.

•        Age: Peak age (l 2 -16 years), unusual in infancy and early childhood.

•        Firm, papules with rough, horny surface.

•        Types: common warts, flat warts, filliform warts, plantar warts, genital warts.

Diagnosis & Investigations

•        Mostly clinical diagnosis.

•        Skin biopsy

Non-pharmacological Treatment

•        Avoid scratching.

•        Avoid sharing of towels, contact sports and communal bathing.

•        Safe sex practice in case of genital warts.

Pharmacological Treatment

•        Wart paint (lactic acid 16% & salicylic acid 16%)

•        Salicylic acid 10-40% under occlusion.

•        Podophyllin 25% weely

•        Trichloroacetic acid 20-100%

•        Cryotherapy using liquid nitrogen.

•        Curettage or diathermy.

•        Tab levamisole 150mg twice a week.