Viral infections Classification of Human Viruses y DNA Viruses : y RNA Viruses : y Herpes Simplex y Retrovirus y Varicella Zoster y Togavirus y Human Papilloma y Flavivirus y Poxvirus y Paramyxovirus y HHV (6,7,8) y Hepatitis A,C,E y Epstein Barr y Picornavirus y Parvovirus y Hepatitis B Aetiopathogenesis y Cell lysis (Herpes) y Cell proliferation (Pox, HPV) y Carcinogenesis (Cervical Ca, Hepatoma) y Exanthemata - Viraemia, Type 3 hypersensitivity (Arthus) reaction, virus lodged in dermal capillaries and replicate in epidermis. y Persistent infection: Periods of latency and reactivation (HSV, VZV) Common Viral Infections of Skin y Human Papilloma Virus: Genital & Non-genital warts y Pox Virus : Molluscum Contagiosum y Varicella Zoster Virus: Varicella, Herpes Zoster y Herpes Simplex Virus I & I I: Herpes Simplex y 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 y Incubation period: few weeks to about one year. y Transmission: direct or indirect contact (nail biters, shaving, occupational, swimming pool.) y Sexual transmission: genital/ perianal wart y Autoinoculation Clinical Types Non genital: Verruca vulgaris (Common warts) Verruca Plana (Plane warts) Filiform Digitate Palmoplantar Periungual Genital: Condyloma Acuminata Clinical features Verruca vulgaris: Commonest type of warts Children and young adults affected Asymptomatic, hyperkeratotic papular lesions with warty excrescences Common Sites: Extremities, dorsae of hands & feet Koebner’s phenomenon present VERRUCA VULGARIS Clinical features Verruca plana: Juvenile/ flat warts Discrete flat skin colored or pigmented papules, coalesce Koebners phenomenon Sites: face, neck, extremities y Filiform: finger like projection y Digitate: Multiple finger like projections with common base Sites: head, face and neck Clinical features y Palmoplantar: Hyperkeratotic elevated or flat lesions, painful on lateral pressure Mosaic and Myrmecia Differential diagnosis: Corn, Callosity y Periungual: Commonly associated with palmoplantar warts, Invasion of nail bed. y Recalcitrant to Rx PALMAR WART PLANTAR WART Genital Warts y Condyloma Acuminata: Protuberant moist ,cauliflower like growths Sites: frenulum, corona and glans in men and posterior fourchette in women Anogenital warts in children: sexual or non-sexual transmission y Bowenoid Papulosis: Multiple, grouped, warty lesions on genitals, premalignant Complications y Secondary infection y Pregnancy related: Proliferative growth, obstruction of labour, laryngeal papillomas in child y Malignant change: Buschke-Lowenstein tumor Cervical intraepithelial neoplasia (HPV 16, 18) Investigations y Clinical diagnosis y Histology: Papillomatosis, acanthosis with inclusion bodies causing vacuolation in cells y Electron microscopy y DNA Hybridisation y Immunohistochemistry : Type of HPV Treatment y Topical Keratolytics : Salicylic Acid, Urea, Wart solution (Lactic acid/Salicylic Acid) Chemical cautery: Podophyllin, TCA Cryotherapy Electrocautery Radiosurgery Laser therapy Others: Imiquimod, 5FU, DNCB, Bleomycin, Interferon Treatment y Systemic Immnomodulators: Levamisole, Cimetidine Interferon Photodynamic Therapy Molluscum Contagiosum y Pox Virus- Molluscum Contagiosum virus y MCV 1 and MCV 2 y Incubation period: 2 weeks to 6 months y Transmission: contact, fomites, sexual. y Intracytoplasmic inclusion bodies Clinical features y Dome shaped, pearly white, discrete umbilicated papules. y Koebner’s phenomenon present y Sites: Face, neck, trunk, peri-genitals (more in sexual transmission), eyelids. y Giant Molluscum Contagiosum / secondary infection. MOLLUSCUM CONTAGIOSUM Molluscum Contagiosum in HIV y Commonly on genitals, perianal region, eyelids y Refractory Mollscum on face y Disseminated lesions y D/D: Cryptococcosis, Histoplasmosis, Penicillinosis Treatment y Expression / Curettage y Chemical cautery, Electrodessication, Cryotherapy. y Topical: Imiquimod, KOH, Phenol, Cantharidine, Cidofovir. y Systemic: Levamisole, Cimetidine Varicella Zoster Virus y Chicken pox and shingles y Transmission: Droplet infection - nasopharynx y Varicella : primary viraemia y Zoster: Reactivation of residual latent virus in the sensory nerve ganglion Varicella - Clinical features y Incubation period: 2-3 weeks y Prodromal symptoms y Pleomorphic, centripetal distribution, dewdrops on rose petal appearance y Vesicles, papulovesicles, crusting, haemorrhagic, umbilicated lesions y Mucosal involvement VARICELLA ZOSTER Complications y Secondary infection y Encephalitis y Pneumonitis y Hepatitis y Varicella in HIV- Progressive, haemorrhagic, complicated y Chronic varicella- Hyperkeratotic lesions, Acute retinal necrosis Treatment y Symptomatic: Rest, Antibiotics, Anti-inflammatory, Calamine lotion y Acyclovir Dose: 800 mg 5 times/day Indicated in adult varicella; reduces severity, duration & infectivity in childhood chicken pox y Prophylaxis: Vaccine, Immunoglobulin, Acyclovir Herpes Zoster Clinical Features y Reactivation of latent virus in the dorsal root ganglion of sensory nerve y Older age group y Unilateral, dermatomal, grouped vesicles y Cranial (V, VII commonly), spinal (thoracic commonly) y Pre-herpetic, herpetic and post-herpetic neuralgia HERPES ZOSTER Herpes Zoster : Cranial nerve involvement V Nerve: y Ophthalmic division: Herpes Zoster Ophthalmicus Hutchinsons sign (vesicles on nose tip) Ocular complications: uveitis, keratitis, conjunctivitis, scleritis, ocular palsy y Maxillary division: uvula / tonsils y Mandibular division : tongue / buccal mucosa Herpes Zoster : Cranial nerve involvement VII nerve : Ramsay Hunt syndrome: y Earache, vesicles on pinna, facial palsy y Hearing loss, vertigo and taste sensation impaired Complications y Secondary infection y Post herpetic neuralgia y Scarring y Nerve Palsy y Encephalitis : in disseminated zoster Herpes Zoster in HIV y Younger patient y Severe pre, herpetic and post-herpetic neuralgia y Multi-dermatomal, cranial nerve involvement y Haemorrhagic, disseminated y Protracted course, verrucous lesions y Acute retinal necrosis Treatment y Symptomatic y Antivirals: Acyclovir 800mg x 5times/day Famciclovir 250-500 mg tds Valaciclovir 1gm tds Duration : 1week in immunocompetent 2weeks in immunosuppressed y Steroids : in cranial nerve involvement Treatment of post herpetic neuralgia y Steroids y Analgesics y Amitryptilline, Doxepine y Phenytoin, Carbamazapine, Sodium valproate y Gabapentine y Methylcobalamine y Topical EMLA cream y Topical capsaicin y Intralesional Steroids Herpes Simplex Virus y HSV 1: Facial (above waist) y HSV 2: Genital (sexual) y Incubation Period : 3-7 days y Primary infection y Persist in sensory ganglion - period of latency y Recurrent infection Clinical features y Grouped vesicles on erythematous base followed by erosions and healing y Primary attack: severe with lymphadenopathy and systemic complaints y Recurrences: mild with shortened clinical course y Predisposing factors: trauma, sunburn, stress, coitus, premenstrual, high grade fever, infections, surgery, dermabrasion Herpes Simplex- Clinical Types y Herpes Simplex Virus I : Herpes Labialis, Herpetic Gingivostomatitis, Herpetic whitlow, Herpetic gladiatorum, Herpes sycosis, Keratoconjunctivitis y Herpes Simplex Virus II: Herpes progenitalis, Herpetic vulvovaginitis y Complicated: Eczema herpeticum, Disseminated HSV y Herpes Simplex Virus in HIV: Chronic, recurrent, ulcer, eschar formation and dissemination Herpes labialis Differential diagnosis y Aphthosis y Erythema multiforme y Behcet’s syndrome y Pyodermas y Chancroid Complications y Radiculoneuropathy y Dissemination y Meningitis / encephalitis y Erythema multiforme y Eczema herpeticum y Ocular complications Investigations y Tzanck smear : Multinucleated giant cells y Histopathology : Ballooning degeneration, intraepithelial blisters, inclusion bodies y HSV antibody titre : IgG/IgM y Culture y Immunofluoroscence, PCR y Electron microscopy Treatment y Symptomatic y Topical: Acyclovir, Penciclovir, Cidofovir y Systemic: Antiviral Primary Recurrence Suppressive (10 days) (5 days) 6months-1yr Acyclovir 200mg 400mg tid 400 mg bd 5times/day Valaciclovir 1gm bd 500mg bd 500-1000 mg bd Famciclovir 250mg tid 125mg bd 250mg bd Viral Exanthems y Macular: Rubella EBV(infectious mononucleosis) Human herpesvirus 6(roseola) Human herpesvirus 7 y Maculopapular : Togavirus Measles Human parvovirus B19 (erythema infectiosum) Viral Exanthems y Maculopapular - vesicular : Coxsackie A (5, 9, 10,16) Echovirus (4, 9, 11) y Maculopapular - petechial: Togavirus (Chikungunya) Bunyavirus haemorrhagic fever (Lassa) y Urticarial: Coxsackie A9 and Hepatitis B Uncommon Viral Infections of the Skin : y Pox Viruses : Cowpox, Orf, Milker’s nodule y Epstein Barr Virus: Infectious Mononucleousis, OHL, Gianotti Crosti, Lymphomas y Viral insect-borne and haemorrhagic fevers: (Toga, Flavi, Arena, Filo, Bunya) Chikungunya, Dengue, Kyasanur Forest Disease, Lassa y Picorna Viruses : Herpangina, hand, foot and mouth disease. 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