Viral Dermatoses Department of Dermatology Xiao Sheng-Xiang

General Description Definition Viral dermatoses are the cutaneous diseases resulting from viral infections.

Classification of Viral dermatoses Herpesvirus group Herpes simplesx Varicella ( Chickenpox ) Herpes Zoster Roseala Infantum ( Sixth disease) Kaposi’s sarcoma

Classification of Viral dermatoses Poxvirus group Molluscum contagiosum, milker’s nodules Papovavirus group Warts(common warts, Flat warts, plantar warts, genital warts)

Classification of Viral dermatoses Parvovirus Erythema infectiosum( fifth disease) (B19 virus) Paramyxovirus group Measles, rubella

Classification of Viral dermatoses Picornavirus group (enteroviruses) Hand-fooot –mouth disease (coxackie virus) Retroviruses AIDS

Herpes Simplex

Etiology Herpes Simplex Virus ( HSV ): DNA Virus Two antigenic types: HSV-1, HSV-2 HSV-1: lesions on the lips, face HSV-2: genital herpes Lesions anywhere may be caused by either antigenic type. Transmission: Intimate contact ( direct inoculation through traumatized skin )

Primary infection and recurrent infection Primary infection: first infection After primary infection virus migrates to the neuronal cells in ganglion latent infection latent 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, appear at the age of onset of sexual activity. USA: ~23% of adults are infected with HSV-2 Developing countries: 60~95% 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. Mature 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 Diagnosis Laboratory Test Tzanck smear: take a smear of cells from the base of the skin lesion spread the cells on a glass slide stain with wright or Giemsa Stain look for multinucleated giant cells Non specific: HSV VZV Accuracy rate: 60~90% False positive rate: 3~12%

Detection of virus antigen of the lesion Materials:vesicular fluid ,cells from the base of skin lesion Methods: direct fluorescent antibody test immunoperoxidase 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 that the viral infection is the cause of the current lesion.

Threatment Therapeutic principle To shorten disease duration To prevent bacterial infection To prevent recurrence

Threatment Anti-HSV therapy Primary infection: Acyclovir: 0.2g, five times/day×7-10days Valaciclovir: 0.3g, bid ×7-10days Famcyclovir: 0.25g, tid ×7-10days Recurrent infection: treatment duration 5 days

Threatment Severe recurrent cases acyclovir 04g bid valacyclovir 0.3g qid famcyclovir 0.25g bid 4M to 1Y

Threatment Other antiviral agents like IFN- or may be applied Topical therapy 1% pencyclonir cream, 1% acyclovir cream, topical antibiotics

Varicella & herpes zoster

Etiology Varicela-zoster virus (VZV): human herpes virus-type 3 Tranmmission: direct contact respiratory route A very communicable disease

Primary infection: varicella or subclinical infection Virus reactivation: herpes zoster Cellular immunity and herpes zoster 90% cases 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 infection

Herpes zoster Features of the lesions: Occurs unilateraly within the distribution of a cranial or spinal sensory nerve Skin 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

Diagnosis , differential diagnosis Herpes zoster and herpes simplex In 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 Antiviral 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

Zoster associated pain Drug therapy: simple analgesics like aspirin Tricyclic antidepresants like amitriptyline anticonvulsants like carbamarepine Local anesthetics: 10% lidocain gel or patches Nerve blocks

Bacterial Dermatoses Impetigo

Etiology 50~70% of cases: staphylococcus aurens The reminder: streptococcus or a combination Occur frequently in children in hot, humid weather Sources of infection for children: pets, dirty fingernails, crowded housing areas

Clinical manifestation Nonbullous impetigo Begins with 2-mm erythematous macules vesicles or bullae seropurulent discharge golden yellow crusts spread by scratching and autoinoculation

Bullous impetigo occurs in new-born infants (4th-5th day of life) bullae in the face, hand and other sites later weakness, fever or subnormal temperature Diarrhea Bacteremia, pneumonia or meningitis

Diagnosis Clinical diagnosis Bacterial examination: gram stain or culture

Treatment Topical agents Rivanol ( Compound Ethacridine Solution) 2% mupirocin ointment other topical antibiotic agents

Systemic agents Antibiotics Semisynthetic penicillin (penicillinase-resistant) like dicioxacillin Cephalosporin Erythromycine, azithromycine Clindamycine

Staphylococcal scalded skin syndrome (SSSS) A generalized, confluent, superficially exfoliative bacterial disease, occurring in neonated and children

Etiology Group 2 staphylococcus aureus, most commonly phage type 71 Epidermolytic exotoxin Infection sites: pharynx, nose, ear, conjunctive, septicemia, cutaneous infection

Clinical manifestations Abrupt fever Skin tenderness Diffuse erythema in the neck, groin, axillae Generalized exfoliation within hours to days, sheets of epidermis separating Positive nikolsky sign Healing within 10 days

Diagnosis Treatment Laboratory findings Leukocyte count,neutrophil proportion Bacterial culture: mucous membranes , skin Treatment Antibiotics Fluid therapy and general supporative measures

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