Viral infections

Classification of Human Viruses

DNA Viruses : Herpes Simplex Varicella Zoster Human PapillomaPoxvirus HHV (6,7,8)Epstein BarrParvovirusHepatitis B

RNA Viruses :RetrovirusTogavirusFlavivirusParamyxovirusHepatitis A,C,E Picornavirus

Aetiopathogenesis

Cell lysis (Herpes)

Cell proliferation (Pox, HPV)

Carcinogenesis (Cervical Ca, Hepatoma)

Exanthemata - Viraemia, Type 3

hypersensitivity (Arthus) reaction, virus lodged

in dermal capillaries and replicate in epidermis.

Persistent infection: Periods of latency and

reactivation (HSV, VZV)

Common Viral Infections of Skin

Human Papilloma Virus: Genital & Non-genital warts

Pox Virus : Molluscum Contagiosum

Varicella Zoster Virus: Varicella, Herpes Zoster

Herpes Simplex Virus I & I I: Herpes Simplex

Viral Exanthems

Human Papilloma Virus: Aetiopathogenesis

Human Papilloma Virus:

DNA virus, 1-80 types

Anogenital warts 6,11,16,18,31,33,51-59,70

Incubation period: few weeks to about one year.

Transmission: direct or indirect contact (nail biters, shaving, occupational, swimming pool.)

Sexual transmission: genital/ perianal wart

Autoinoculation

Clinical TypesNon genital: Verruca vulgaris (Common warts)

Verruca Plana (Plane warts)FiliformDigitate Palmoplantar Periungual

Genital: Condyloma Acuminata

Clinical featuresVerruca vulgaris: Commonest type of wartsChildren and young adults affectedAsymptomatic, hyperkeratotic papular lesions with warty excrescences Common Sites: Extremities, dorsae of hands & feetKoebner’s phenomenon present

VERRUCA VULGARIS

Clinical featuresVerruca plana: Juvenile/ flat wartsDiscrete flat skin colored or pigmented papules, coalesceKoebners phenomenonSites: face, neck, extremities

Filiform: finger like projectionDigitate: Multiple finger like projections with common base

Sites: head, face and neck

Clinical featuresPalmoplantar: Hyperkeratotic elevated or flat lesions, painful on lateral pressureMosaic and MyrmeciaDifferential diagnosis: Corn, CallosityPeriungual: Commonly associated with palmoplantar warts,Invasion of nail bed.Recalcitrant to Rx

PALMAR WART PLANTAR WART

Genital WartsCondyloma Acuminata:

Protuberant moist ,cauliflower like growths Sites: frenulum, corona and glans in men andposterior fourchette in womenAnogenital warts in children: sexual or non-sexual transmission

Bowenoid Papulosis: Multiple, grouped, warty lesions on genitals, premalignant

ComplicationsSecondary infectionPregnancy related:Proliferative growth, obstruction of labour, laryngeal papillomas in childMalignant change:Buschke-Lowenstein tumorCervical intraepithelial neoplasia (HPV 16, 18)

InvestigationsClinical diagnosisHistology: Papillomatosis, acanthosis with inclusion bodies causing vacuolation in cells

Electron microscopyDNA HybridisationImmunohistochemistry : Type of HPV

TreatmentTopical Keratolytics :Salicylic Acid, Urea, Wart solution (Lactic acid/Salicylic Acid) Chemical cautery: Podophyllin, TCACryotherapyElectrocauteryRadiosurgeryLaser therapyOthers: Imiquimod, 5FU, DNCB, Bleomycin, Interferon

TreatmentSystemic Immnomodulators: Levamisole, CimetidineInterferon Photodynamic Therapy

Molluscum Contagiosum

Pox Virus- Molluscum Contagiosum virus

MCV 1 and MCV 2

Incubation period: 2 weeks to 6 months

Transmission: contact, fomites, sexual.

Intracytoplasmic inclusion bodies

Clinical features

Dome shaped, pearly white, discrete umbilicated

papules.

Koebner’s phenomenon present

Sites: Face, neck, trunk, peri-genitals (more in

sexual transmission), eyelids.

Giant Molluscum Contagiosum / secondary

infection.

MOLLUSCUM CONTAGIOSUM

Molluscum Contagiosum in HIV

Commonly on genitals, perianal region, eyelids

Refractory Mollscum on face

Disseminated lesions

D/D: Cryptococcosis, Histoplasmosis,

Penicillinosis

Treatment

Expression / Curettage

Chemical cautery, Electrodessication,

Cryotherapy.

Topical: Imiquimod, KOH, Phenol, Cantharidine,

Cidofovir.

Systemic: Levamisole, Cimetidine

Varicella Zoster Virus

Chicken pox and shingles

Transmission: Droplet infection - nasopharynx

Varicella : primary viraemia

Zoster: Reactivation of residual latent virus in the

sensory nerve ganglion

Varicella - Clinical features

Incubation period: 2-3 weeks

Prodromal symptoms

Pleomorphic, centripetal distribution, dewdrops

on rose petal appearance

Vesicles, papulovesicles, crusting, haemorrhagic,

umbilicated lesions

Mucosal involvement

VARICELLA ZOSTER

Complications

Secondary infection

Encephalitis

Pneumonitis

Hepatitis

Varicella in HIV- Progressive, haemorrhagic,

complicated

Chronic varicella- Hyperkeratotic lesions, Acute

retinal necrosis

Treatment

Symptomatic:

Rest, Antibiotics, Anti-inflammatory, Calamine lotion

Acyclovir

Dose: 800 mg 5 times/day

Indicated in adult varicella; reduces severity,

duration & infectivity in childhood chicken pox

Prophylaxis:

Vaccine, Immunoglobulin, Acyclovir

Herpes Zoster

Clinical FeaturesReactivation of latent virus in the dorsal root ganglion of sensory nerve

Older age group

Unilateral, dermatomal, grouped vesiclesCranial (V, VII commonly), spinal (thoracic commonly)

Pre-herpetic, herpetic and post-herpetic neuralgia

HERPES ZOSTER

Herpes Zoster : Cranial nerve involvement

V Nerve:

Ophthalmic division: Herpes Zoster OphthalmicusHutchinsons sign (vesicles on nose tip)Ocular complications: uveitis, keratitis, conjunctivitis, scleritis, ocular palsy

Maxillary division: uvula / tonsils

Mandibular division : tongue / buccal mucosa

Herpes Zoster : Cranial nerve involvement

VII nerve :

Ramsay Hunt syndrome:

Earache, vesicles on pinna, facial palsy

Hearing loss, vertigo and taste sensation

impaired

Complications

Secondary infection

Post herpetic neuralgia

Scarring

Nerve Palsy

Encephalitis : in disseminated zoster

Herpes Zoster in HIV

Younger patient

Severe pre, herpetic and post-herpetic neuralgia

Multi-dermatomal, cranial nerve involvement

Haemorrhagic, disseminated

Protracted course, verrucous lesions

Acute retinal necrosis

Treatment

Symptomatic

Antivirals:

Acyclovir 800mg x 5times/day

Famciclovir 250-500 mg tds

Valaciclovir 1gm tds

Duration : 1week in immunocompetent

2weeks in immunosuppressed

Steroids : in cranial nerve involvement

Treatment of post herpetic neuralgia Steroids

Analgesics

Amitryptilline, Doxepine

Phenytoin, Carbamazapine, Sodium valproate

Gabapentine

Methylcobalamine

Topical EMLA cream

Topical capsaicin

Intralesional Steroids

Herpes Simplex Virus

HSV 1: Facial (above waist)

HSV 2: Genital (sexual)

Incubation Period : 3-7 days

Primary infection

Persist in sensory ganglion - period of latency

Recurrent infection

Clinical features

Grouped vesicles on erythematous base followed

by erosions and healing

Primary attack: severe with lymphadenopathy

and systemic complaints

Recurrences: mild with shortened clinical course

Predisposing factors: trauma, sunburn, stress,

coitus, premenstrual, high grade fever, infections,

surgery, dermabrasion

Herpes Simplex- Clinical TypesHerpes Simplex Virus I : Herpes Labialis, Herpetic Gingivostomatitis, Herpetic whitlow, Herpetic gladiatorum, Herpes sycosis, KeratoconjunctivitisHerpes Simplex Virus II: Herpes progenitalis, Herpetic vulvovaginitisComplicated: Eczema herpeticum, Disseminated HSV Herpes Simplex Virus in HIV:Chronic, recurrent, ulcer, eschar formation and dissemination

Herpes labialis

Differential diagnosisAphthosis

Erythema multiforme

Behcet’s syndrome

Pyodermas

Chancroid

ComplicationsRadiculoneuropathy

Dissemination

Meningitis / encephalitis

Erythema multiforme

Eczema herpeticum

Ocular complications

InvestigationsTzanck smear : Multinucleated giant cells

Histopathology : Ballooning degeneration,

intraepithelial blisters, inclusion bodies

HSV antibody titre : IgG/IgM

Culture

Immunofluoroscence, PCR

Electron microscopy

TreatmentSymptomatic

Topical: Acyclovir, Penciclovir, Cidofovir

Systemic:

Antiviral Primary(10 days)

Recurrence(5 days)

Suppressive6months-1yr

Acyclovir 200mg 5times/day

400mg tid 400 mg bd

Valaciclovir 1gm bd 500mg bd 500-1000 mg bd

Famciclovir 250mg tid 125mg bd 250mg bd

Viral ExanthemsMacular:

Rubella

EBV(infectious mononucleosis)

Human herpesvirus 6(roseola)

Human herpesvirus 7

Maculopapular :

TogavirusMeasles

Human parvovirus B19 (erythema infectiosum)

Viral ExanthemsMaculopapular - vesicular :

Coxsackie A (5, 9, 10,16)

Echovirus (4, 9, 11)

Maculopapular - petechial:

Togavirus (Chikungunya)

Bunyavirus haemorrhagic fever (Lassa)

Urticarial:

Coxsackie A9 and Hepatitis B

Uncommon Viral Infections of the Skin :Pox Viruses :Cowpox, Orf, Milker’s noduleEpstein Barr Virus: Infectious Mononucleousis, OHL, Gianotti Crosti, LymphomasViral insect-borne and haemorrhagic fevers:(Toga, Flavi, Arena, Filo, Bunya)Chikungunya, Dengue, Kyasanur Forest Disease, LassaPicorna Viruses :Herpangina, hand, foot and mouth disease.

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