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1、Viral Dermatoses Department of Dermatology Xiao Sheng-Xiang,General Description,DefinitionViral dermatoses are the cutaneous diseases resulting from viral infections.,Classification of Viral dermatoses,Herpesvirus group Herpes simplesxVaricella ( Chickenpox ) Herpes ZosterRoseala Infantum ( Sixth di
2、sease) Kaposis sarcoma,Classification of Viral dermatoses,Poxvirus groupMolluscum contagiosum, milkers nodulesPapovavirus groupWarts(common warts, Flat warts,plantar warts, genital warts),Classification of Viral dermatoses,ParvovirusErythema infectiosum( fifth disease) (B19 virus)Paramyxovirus group
3、Measles, rubella,Classification of Viral dermatoses,Picornavirus group (enteroviruses)Hand-fooot mouth disease (coxackie virus)RetrovirusesAIDS,Herpes Simplex,Etiology,Herpes Simplex Virus ( HSV ): DNA Virus Two antigenic types: HSV-1, HSV-2HSV-1: lesions on the lips, faceHSV-2: genital herpesLesion
4、s anywhere may be caused by eitherantigenic type. Transmission: Intimate contact ( direct inoculation through traumatized skin ),Primary infection and recurrent infectionPrimary infection: first infectionAfter primary infection virus migrates to the neuronal cells in ganglion latent infection latent
5、 virus to reactivate by triggering factors virus particles move on the nerve replicate in the epithelial cells recurrent infection Triggering factors: fever, trauma, emotional stress, menstruation,Epidemiology,85% of adults worldwide are seropositire for HSV-1. Seroprevalence for HSV-2 is lower, app
6、ear at the age of onset of sexual activity. USA: 23% of adults are infected with HSV-2Developing countries: 6095% of infection rates of HSV-2 Incubative or subclinical infection: 90% of all infected,Clinial manifestation,Features of the lesion: multiple small papules, vesicles, clusted together.Matu
7、re lesion: grouped vesicles and / or pustules on an erythematous edematous base Common site for lesions: face, lips, mouth, neck, anogenital area Heal within 1-2 weeks,Diagnosis,Clinical DiagnosisLaboratory Test Tzanck smear: take a smear of cells from the base of the skin lesion spread the cells on
8、 a glass slide stain with wright or Giemsa Stain look for multinucleated giant cells Non specific: HSV VZV Accuracy rate: 6090% False positive rate: 312%,Detection of virus antigen of the lesionMaterials:vesicular fluid ,cells from the base of skin lesionMethods: direct fluorescent antibody test imm
9、unoperoxidase tchniques Virus culture,Emphasis,Serologic tests (detection of anti-HSV antibody of the blood) are generally not used in determining whether a skin lesion is due to HSV infection. A positive result to a serologic test indicates only that the individual is infected with that virus, not
10、that the viral infection is the cause of the current lesion.,Threatment,Therapeutic principleTo shorten disease durationTo prevent bacterial infectionTo prevent recurrence,Threatment,Anti-HSV therapyPrimary infection: Acyclovir: 0.2g, five times/day7-10daysValaciclovir: 0.3g, bid 7-10daysFamcyclovir
11、: 0.25g, tid 7-10daysRecurrent infection: treatment duration 5 days,Threatment,Severe recurrent casesacyclovir 04g bidvalacyclovir 0.3g qidfamcyclovir 0.25g bid 4M to 1Y,Threatment,Other antiviral agents like IFN- or may be applied Topical therapy1% pencyclonir cream,1% acyclovir cream, topical anti
12、biotics,Varicella & herpes zoster,Etiology,Varicela-zoster virus (VZV): human herpes virus-type 3 Tranmmission:direct contactrespiratory route A very communicable disease,Primary infection: varicella or subclinical infection Virus reactivation: herpes zoster Cellular immunity and herpes zoster 90% c
13、ases of varicela 10 years of age,Clinical manifestation,Varicella Skin lesion: macules vesicles (within 24hs) successive fresh vesicles (within 4 days) Hemorrhagic, necrotic or bullous lesion,The site of lesions: trunck, face, oral mucosa Other symptoms: fever (moderate )pruritus, secondary infectio
14、n,Herpes zoster Features of the lesions:Occurs unilateraly within the distribution of a cranial or spinal sensory nerveSkin lesions: papules, plaques of erythema, blisters in the dermatome Pain associated with herpes zoster Disease duration: 2-3weeks in the younger, 6 weeks or more in the elderly,Di
15、agnosis , differential diagnosis,Herpes zoster and herpes simplexIn the early stages of herpes zoster, if the number of lesions of zoster is limited, it can be relatively indistinguishable from herpes simplex.Herpes zoster: more painfull, progress to involve more area over 24hs,Treatment,Varicella A
16、ntiviral therapy acyclovir 20mg/kg/d 5days ,not routinly recommended Topical antipruritic lotions,Herpes Zoster,General therapy Restrict physical activities Local applications of heat Topical anesthetics, antipruritic lotion, topical antiviral agents Vesicular stage: cool compress,Antiviral therapy: reduce the duration of pain Start preferably within the first 3 or 4 days Severe cases: intravenous therapy (acyclovir, 5mg/kg, tid) Refrence doses Acyclovir 0.8g 5times/day 7 days Valaciclovir 1.0g tid 7 days Famciclovir 0.5g tid 7 days,
