Viral infections i,ii,iii

Viral Infections of SKIN AND MUCOSA I

AAU-MFDept. of

Dermato-venereology

HUMAN HERPESVIRUSES

• Human herpesviruses (HHVs) (family Herpesviridae)are defined by the architecture of the virion,which has: Core containing a linear double-strand DNA• Icosahedral capsid 100–110 nm in diameter composed of 162 capsomers Envelope containing

viral glycoprotein spikes on the surface.• Worldwide, 60–90% of the population is infected with one or more HHVs.

Eight HHVs have been identified:▪ Herpes simplex virus (HSV)-1 (HHV-1)▪ HSV-2 (HHV-2)▪ Varicella-zoster virus (VZ V, or HHV-3)▪ Epstein-Barr virus (EBV, or HHV-4)▪ Cytomegalovirus (CMV, or HHV-5)▪ HHV-6▪ HHV-7▪ HHV-8 (Kaposi sarcoma–associated virus). Primary HHV infections are usually asymptomatic with the exception of VZV, which nearly always presents with symptomatic varicella.

After primary infection, HHVs remain latent in neural or lymphoid cells and reactivate if an adequate immune response does not exist.HHVs are categorized into three groups: Alpha, beta, and gamma Herpesviridae ▪ Alpha Herpesviridae : HSV-1, HSV-2, VZV are characterized by a variable host range, relatively short reproductive cycle, rapid spread in culture, rapid destruction of infected cells, and latentinfection primarily, but not exclusively, of sensory ganglia.

Beta Herpesviridae : CMV has a restricted hostrange and spreads slowly in cultures.Gamma Herpesviridae : EBV, HHV-6, HHV-7,HHV-8, and herpesvirus saimiri are lymphotropic,specific for either T or B lymphocytes.The HHV-8 DNA sequences are closely homologousto minor capsid and tegument protein genes of gamma herpesviridae EBV and herpesvirusSaimiri.

HERPES SIMPLEX VIRUS (HSV) INFECTION

• Whether first-symptomatic or recurrent, may “typically” present clinically with grouped vesicles arising on an erythematous base on keratinized skin

or mucous membrane.• Most HSV infections are “atypical,” with patch(es) of

erythema, small erosions, fissures, or subclinical lesions that shed HSV.

• Once an individual is infected, HSV persists in sensory ganglia for the life of the patient, recurring

with lessening in immunity.

• Age of Onset Most commonly young adults;• range, infancy to senescence.• Etiology HSV-1, HSV-2.• Labialis: HSV-1 (80–90%), HSV-2 (10–20%).• Urogenital: HSV-2 (70–90%), HSV-1 (10–30%).• Herpetic whitlow: <20 years of age usuallyHSV-1; >20 years of age, usually HSV-2.• Neonatal: HSV-2 (70%), HSV-1 (30%).

Herpes simplex virusinfection: herpetic whitlow

Transmission

• Most transmission occurs when persons shed virus but lack lesions.

• Usually skin-skin, skin-mucosa, mucosa-skin contact. Herpes gladiatorum transmitted by skin to-skin contact

in wrestlers.• Increased HSV-1 transmission associated with crowded living conditions and lower socioeconomic status

Immunocompromising Factors Predisposing to HSV Reactivation

• HIV/AIDS infection, • Malignancy (leukemia/lymphoma), • Transplantation (bone marrow, solid organ),• Chemotherapy,• Systemic glucocorticoids, • Other immunosuppressive drugs, • Radiotherapy

PATHOGENESIS

• Primary HSV infection occurs through close contact with a person shedding virus at a peripheral site, mucosal surface, or secretion.

• HSV is inactivated promptly at room temperature;aerosol or fomitic spread unlikely.• Infection occurs via inoculation onto susceptible mucosal surface or break in skin.• After exposure to HSV, the virus replicates in epithelial

cells, causing lysis of infected cells, vesicle formation, and local inflammation.

After primary infection at inoculation site, HSVascends peripheral sensory nerves and enterssensory or autonomic nerve root (vagal) ganglia, where latency is established.• Retrograde transport of HSV among nervesand establishment of latency are not dependent on viral replication in skin or neurons; neurons can be infected in the absence of symptoms

• Latency can occur after both symptomaticand asymptomatic primary infection.

Periodically, HSV may reactivate from its latent state and virus particles then travel along sensory neurons to skin and mucosal sites to cause recurrent disease episodes.

• Recurrent mucocutaneous shedding can be associated with or without (asymptomatic shedding) lesions; virus can be transmitted to a new host when shedding occurs.

LABORATORY EXAMINATIONS

• Direct Microscopy Tzanck Smear• Optimally, fluid from intact vesicle is smeared

thinly on a microscope slide, dried, and stained with either Wright or Giemsa stain. Positive, if acantholytic keratinocytes or multinucleated giant acantholytic keratinocytes are detected.

• Positive in 75% of early cases, either primary or recurrent.

Herpes simplex virus: positive Tzanck smear

Antigen Detection DFA Monoclonal antibodies,specific for HSV-1 and HSV-2 antigens, detect and differentiate HSV antigens on smear from lesion.Cultures: Positive HSV cultures from involvedmucocutaneous site or tissue biopsy specimens.Serologyspecific• Antibodies to glycoprotein (g)G1 and (g)G2detect and differentiate past HSV-1 and HSV-2infections.

• Primary HSV infection can be documentedby demonstration of seroconversion.• Recurring herpes can be ruled out if seronegative for HSV antibodies.Polymerase Chain Reaction: To determineHSV-DNA sequences in tissue, smears, orsecretion.

DIAGNOSIS:-Clinical suspicion confirmed by viral cultureor antigen detection. Cultures used for diagnosing first-episode infections since antibodies to (g)H1 or (g)G2 may take 2–6 weeks to develop.

MANAGEMENT

• Prevention:- Skin-to-skin contact should be avoided during outbreak of cutaneous HSV infection.

• Topical Antiviral Therapy:-• Approved for herpes labialis; minimal efficacy.• Acyclovir 5% ointment Apply q3h, 6 times daily for 7 days.

Approved for initial genital herpes and limited mucocutaneous HSV infections in immunocompromised individuals.

• Penciclovir 1% cream Apply q2h while awake for recurrent orolabial infection in immunocompetent

individuals.

Oral Antiviral Therapy

• Drugs for oral HSV therapy include acyclovir, valacyclovir, and famciclovir.

• Valacyclovir, the prodrug of acyclovir, has a better bioavailability and is nearly 85% absorbed after oral administration.

• Famciclovir is equally effective for cutaneous HSV infections.

• Antiviral agents more effective in treating primary infections than recurrences

Acyclovir 400 mg 3 times daily or 200 mg 5 times daily for 7–10 daysValacyclovir 1 g twice daily for 7–10 daysFamciclovir 250 mg 3 times daily for 5–10 daysRecurrences Most episodes of recurrent herpes do not benefit from pulse therapy with oralacyclovir. In severe recurrent disease, patients who start therapy at the beginning of the prodrome or within 2 days after onset of lesions may benefit from therapy by shortening and reducing severity of eruption; however, recurrences cannot be prevented.

Chronic suppression:- Decreases frequency of symptomatic recurrences and asymptomatic HSVshedding. After 1 year of continuous daily suppressive therapy, acyclovir shouldbe discontinued to determine the recurrence rate.Acyclovir 400 mg twice dailyValacyclovir 500–1000 mg per dayFamciclovir 250 mg twice daily

Mucocutaneous disease in immunocompromised:-Patients with herpes who do not respond to theindividuals recommended dose of acyclovir may require a higher oral dose of acyclovir,IV acyclovir, or be infected with an acyclovir-resistant HSV strain, requiring IV foscarnet. • Acyclovir 5 mg/kg IV q8h for 7–14 days, or 400

mg 5 times daily for 7–14 daysNeonatal:-Acyclovir 20 mg/kg IV q8h for 14–21 days

Herpes simplex virus infection: eczema herpeticum on eyelids

ComplicationsMeningitisBell’s palsyKeratoconjunctivitisEczema herpeticum

VIRAL INFECTIONS OFSKIN AND MUCOSA II

AAU-MFDepartment of

Dermato-Venereology

• Viral infections of skin and mucosa produce a wide spectrum of clinical manifestations.• Viruses that cause febrile illness with exanthems are usually self-limited, with primary infection conveying lifetime immunity.• Viruses such as human papillomavirus (HPV) and molluscum contagiosum virus (MCV) colonize the epidermis of most individuals without

causing any clinical lesions.

• Benign epithelial proliferations, i.e., warts and molluscum, occur in some colonized persons, are transient, and eventually resolve without therapy.

• In immunocompromised individuals, however, these lesions may become extensive, persistent, and refractory to therapy.

• The eight human herpesviruses often have asymptomatic primary infection but are characterized by lifelong latent infection.

• In the setting of immunocompromised, herpesviruses can become active and cause disease with significant morbidity and mortality rates.

POXVIRUS INFECTIONS

•The poxvirus family is a diverse group of epitheliotropic viruses that infect humans and animals.• The genera of poxviruses that infect humans include

orthopoxvirus, parapoxvirus, molluscipoxvirus, and yatapoxvirus .

• Only smallpox virus (SPV) and molluscum contagiosum virus (MCV) cause natural disease in

humans.

• Small pox (SPV) and monkey pox virus typically cause systemic disease with rash; other poxviruses cause localized skin lesions.

▪ Other poxviruses are associated with zoonotic infections.• Poxviruses are the largest of all animal viruses and

have a double-strand DNA genome.

• They are the only DNA viruses that replicate in cytoplasm, where accumulated viral particles form

eosinophilic inclusions, or Guarnieri bodies, visible by light microscopy (200–400 μm).

• Poxviruses appear as brick-shaped or oval virus particles by electron microscopy.• The nucleosome contains double-strand DNA, which

is surrounded by a membrane.

• Smallpox, or variola, has been eradicated as a naturally occurring infection.

• Cowpox is an infection of cattle caused by cowpox virus.

• The origins of vaccinia virus, which is used to immunize humans against smallpox, are uncertain. It may be derived from variola virus,

cowpox virus, or be a hybrid of the two.

MOLLUSCUM CONTAGIOSUM

• Molluscum contagiosum (MC) is a self-limited• epidermal viral infection.• Risk groups– Children– Immunocompromised: HIV/AIDS, – organ transplant recipients– Sexually active adults

• Skin-colored papules; often umbilicated• Few to myriads of lesions• HIV/AIDS: large nodules; confluent

course• Healthy persons: MC resolves spontaneously• HIV/AIDS: if not successfully treated with

antiretroviral therapy (ART), MC can become huge and confluent.

Clinical manifestations:

Etiology• Molluscum contagiosum virus.• Four discrete viral subtypes, I, II, III, IV.• 30% homology with smallpox virus.• The virus has not been cultured.• Not distinguishable from other poxviruses by

electron microscopy.• In many healthy adults, the epidermis and

infundibulum of hair follicle are colonized by MCV.

Transmission: Skin-to-skin contact.Classification by Risk GroupsChildren• Mollusca commonly occur on exposed skin sites.• Child-to-child transmission relatively low.• Resolve spontaneously.

Sexually Active Adults• Occur in genital region.• Virus transmitted during sexual activity.• Resolve spontaneously.

HIV/AIDS: Organ Transplant Recipients• Most commonly occur on the face, spread by shaving.• With response to ART, lesions often resolve.• Without aggressive therapy in advanced HIV/AIDS, mollusca enlarge; spontaneous regression does not occur.

CLINICAL MANIFESTATIONSDuration of Lesions• In the normal host, mollusca usually persists up to 6 months and then undergo spontaneous regression.• In HIV/AIDS without effective ART, molluscapersist and proliferate even after aggressivelocal therapy.Skin Symptoms• Usually none.• Cosmetic disfigurement.• Concern about having a transmissible infection.• Painful if superinfected.

Mucocutaneous Lesions• Papules (1–2 mm), nodules (5–10 mm)(rarely, giant) Pearly white or skin-colored. Round, oval, hemispherical, UmbilicatedMost larger mollusca have a central keratoticplug which gives the lesion a central dimple or umbilication, best observed after light liquid nitrogen freeze. Gentle pressure on a molluscum causes the central plug to be extruded.• Autoinoculation is apparent in that molluscaare clustered at a site such as the axilla

Host immune response to viral antigen resultsin an inflammatory halo around MC i.e., “MC dermatitis,” which usually heralds spontaneous regression; purulence may occur.• MC can be extensive in organ transplant recipients• In HIV-infected males who shave, mollusca can be confined to the beard area. Hundreds of lesions occur in HIV/AIDS patients

DIAGNOSISUsually made on clinical findings.Biopsy lesion in HIV-infected individual if disseminated invasive fungal infection is in the differential diagnosis.

MANAGEMENTPrevention Avoid skin-to-skin contact with individual having mollusca. HIV-infected individuals with mollusca in the beard area should be advised to minimize shaving facial hair or grow a beard.

Supportive therapy In immunocompetent children and sexually active adults, mollusca regressspontaneously; painful aggressive therapy is not indicated.Treatment of lesionsTopical patient-directed therapy 5% imiquimod cream applied at bedtime 3–5 times per week for up to1–3 months. Clinician-directed therapy (office) These procedures are painful and traumatic, especially for young children. EMLA cream applied to lesions 1 h before therapy may reduce/eliminate pain.Curettage Small mollusca can be removed with a small curette with little discomfort or pain.

Cryosurgery Freezing lesions for 10–15 s is effective and minimally painful, using either a cotton-tipped applicator or liquid nitrogen spray.

Electrodesiccation For mollusca refractory to cryosurgery, especially in HIV-infected individuals with numerous and/or large lesions, electrodesiccation or laser surgery is the treatment of choice. Large lesions usually require injected lidocaine anesthesia. Giant mollusca may require several cycles of electrodesiccation and curettage to remove the large bulk of lesions; these lesions may extend through the dermis into the subcutaneous fat.

Human Papillomavirus Infections

• Human papillomaviruses (HPV) are ubiquitous inhumans, causing subclinical infection▪ Wide variety of benign clinical lesions on skin and mucous membranes.• They also have a role in the oncogenesis of

cutaneous and mucosal premalignancies :▪ Squamous cell carcinoma in situ (SCCIS)▪ Invasive SCC

Cutaneous warts:Cutaneous HPV infections occur commonly in thegeneral population:▪ Common warts: Represent approximately 70%of all cutaneous warts, occurring in up to 20%of all school-age children.• Butcher’s warts: Common in butchers, meatpackers, fish handlers.▪ Plantar warts: Common in older children andyoung adults, accounting for 30% of cutaneouswarts. Flat warts: Occur in children and adults,accounting for 4% of cutaneous warts

Mucosal warts:▪ Condyloma acuminatum (genital wart), most prevalent sexually transmitted infection.▪ Some HPV types have a major etiologic role inthe pathogenesis of in situ as well as invasiveSCC of the anogenital epithelium.▪ During delivery, maternal genital HPV infectioncan be transmitted to the neonate, resulting in• Anogenital warts• Respiratory papillomatosis after aspiration ofthe virus into the upper respiratory tract.

HUMAN PAPILLOMAVIRUS: CUTANEOUS INFECTIONS

• Certain human HPV types commonly infect keratinized skin.

• Cutaneous warts are:▪ Discrete benign epithelial hyperplasia with varying degrees of surface hyperkeratosis▪ Manifested as minute papules to large plaques lesions may become confluent, forming a mosaic.• The extent of lesions is determined by the immune status of the host.

Transmission• Skin-to-skin contact.• Minor trauma with breaks in stratum corneumfacilitates epidermal infection.• Contagion occurs in groups—small (home)or large (school gymnasium)

Other Factors• Immunosuppression associated with an increased incidence of and more widespread cutaneous warts: HIV/AIDS• Iatrogenic immunosuppression with solidorgan transplantation.• Occupational risk associated with meat handling.• Epidermodysplasia verruciformis (EDV): most commonly autosomal recessive.

CLINICAL MANIFESTATIONDuration of Lesions: Warts often persist for several years if not treated

Symptoms• Cosmetic disfigurement.• Plantar warts act as a foreign body and can bequite painful during normal daily activities,such as walking, if located over pressure points.• More aggressive therapies such as cryosurgeryoften result in much more pain than thatcaused by the wart itself.• Bleeding, especially after shaving.

Skin LesionsVerruca Vulgaris (Common Wart)• Firm papules, 1–10 mm or rarely larger hyperkeratotic, clefted surface,with vegetations.• Palmar lesions disrupt the normal line of fingerprints. Return of finger prints is a sign of resolution of the wart.Characteristic “red or brown dots” are betterseen with hand lens and are pathognomonic,representing thrombosed capillary loops.

• Isolated lesion, scattered discrete lesions.• Linear arrangement : inoculation by scratching Annular warts : at sites of prior therapy. Occur at

sites of trauma: hands, fingers, knees.• Butcher’s warts : large cauliflower-like lesionson hands of meat handlers.• Filiform warts: have relatively small bases,extending out with elongated cap.

Verruca vulgaris: thumb

Verruca vulgaris: hand

Verruca vulgaris: hand

Verruca Plantaris (Plantar Wart)• Early small, shiny, sharply marginated papule → plaque with rough hyperkeratoticsurface, studded with brown-black dots(thrombosed capillaries).• As with palmar warts, normal dermatoglyphicsare disrupted. Return of dermatoglyphicsis a sign of resolution of the wart.• Warts heal without scarring.• Therapies such as cryosurgery and electrosurgery can result in scarring at treatment sites.

Tenderness may be marked, especially incertain acute types and in lesions over sites ofpressure (metatarsal head).• Mosaic warts : Confluence of many small warts• “Kissing” warts : lesion may occur on opposingsurface of two toes .• Plantar foot, often solitary but may be threeto six or more.• Pressure points, heads of metatarsal, heels, toes.

Verruca Plana (Flat Wart)• Sharply defined, flat papules (1–5 mm); “flat”surface; the thickness of the lesion is 1–2 mm• Skin-colored or light brown.• Round, oval, polygonal, linear lesions (inoculation of virus by scratching).• Occur on face, beard area , dorsa of hands ,shins.

Verruca plana A 12-year-old male kidney transplant recipient. Multiple brown keratotic papules are seen on the forehead and scalp.

Epidermodysplasia Verruciformis• Autosomal recessive condition.• Flat-topped papules.• Pityriasis versicolor–like lesions, particularlyon the trunk.•Seborrheic keratosis–like lesions and • actinic keratosis–like lesions.Color: skin-colored, light brown, pink, hypopigmented.• Lesions may be numerous, large, and confluent.

• Linear arrangement after traumatic inoculation.• Distribution : face, dorsa of hands, arms, legs, anterior trunk.• Premalignant and malignant lesions arisemost commonly on face.• SCC: in situ and invasive.

DIAGNOSIS• Usually made on clinical findings.• In the immunocompromised host, HIV inducedSCC at periungual sites or anogenital region should be ruled out by lesional biopsy.

MANAGEMENT Goal Aggressive therapies, which are often quite painful and may be followed by scarring, are usually to be avoided because the natural history of cutaneous HPV infections is for spontaneous resolution in months or a few years.

Plantar warts that are painful because of their location warrant more aggressive therapies.

HUMAN PAPILLOMAVIRUS: MUCOSAL INFECTIONS

• Mucosal HPV infections are the most common STIs seen by the dermatologist.

• Only 1–2% of HPV-infected individuals have any visibly detectable clinical lesion.• HPV present in the birth canal can be transmitted to a newborn during vaginal delivery and can cause▪ External genital warts (EGW)• ▪ Respiratory papillomatosis• Warts: barely visible papules to nodules to confluent

masses occurring on:

▪ Anogenital: skin or mucosa▪ Oral mucosa HPV dysplasia of anogenital and oral skin andmucosa ranging from:▪ Mild to severe to squamous cell carcinoma(SCC) in situ (SCCIS)▪ Invasive SCC can arise within SCCIS▪ Most commonly in cervix, anal canal.

VARICELLA ZOSTER VIRUS INFECTIONS

• Varicella zoster virus (VZV) is a human herpesvirus that infects 98% of adult populations.

• Primary VZV infection (varicella or chickenpox) is nearly always symptomatic and characterized by disseminated pruritic vesicles.

• During primary infection, VZV establishes lifelong infection in sensory ganglia.

When immunity to VZV declines, VZV reactivateswithin the nerve cell, traveling down the neuronto the skin, where it erupts in a dermatomal pattern, i.e., herpes zoster (HZ), or shingles.In the immunocompromised host, primary and reactivated VZV infection is often more severe, associated with higher morbidity rates and some mortality. VZV vaccine has reduced the incidence of varicella and herpes zoster.

Age of Onset• Without immunization, 90% of cases occur inchildren <10 years, <5% in persons older than15 years.• With immunization (Varivax), the incidenceis markedly reduced.Etiology• VZV, a herpesvirus.• Structurally similar to other herpesviruses:Lipid envelope surrounding nucleocapsid with icosahedral symmetry.Centrally located double-strand DNA witha molecular weight of 80 million

Transmission• Airborne droplets as well as direct contact• Indirect contact uncommon• Patients are contagious several days beforevaricella exanthem appears and until last cropof vesicles• Crusts are not infectious.• VZV can be aerosolized from skin of individualswith herpes zoster, which is aboutone-third as contagious as varicella, causingvaricella in susceptible contacts.

PATHOGENESIS• In varicella, VZV is thought to enter throughmucosa of upper respiratory tract and oropharynx.• Followed by local replication and primary viremia.• VZV then replicates in cells of reticuloendothelialsystem with subsequent secondary viremia and dissemination to skin and mucous membranes.• Localization of VZV in the basal cell layeris followed by virus replication, ballooningdegeneration of epithelial cells, and accumulationof edema fluid.• Second episodes of varicella have been documentedbut are rare.

LABORATORY EXAMINATIONS

• VZV Antigen Detection DFASmear of vesicle fluid or scraping from ulcer

base/margin: Direct• fluorescent antibody (DFA) test detects VZV specific

antigens.• Viral Cultures: Isolation of virus on viral culture (human fibroblast monolayers) from vesicular

skin lesions, biopsy specimens, cornealscraping, and CSF is possible but more difficultthan for HSV.

Tzanck Smear Cytology of fluid or scrapingfrom base of vesicle or pustule showsboth giant and multinucleated acantholyticepidermal cells (as does that of HSV infections)Serology Seroconversion documents primary VZV infection.

CLINICAL MANIFESTATIONIncubation Period 14 days (range, 10–23 days).Prodrome• Characteristically absent or mild.• Uncommon in children, more common inadults: headache, general aches and pains,severe backache, malaise.• Exanthem appears within 2–3 days. Skin Symptoms Exanthem usually quite pruritic.Skin LesionsIn most children, illness begins with appearanceof exanthem:• Vesicular lesions evident in successivecrops.

• Often single, discrete lesions or scanty in number in children and much more dense in adults.• Initial lesions are papules (often not observed) that may appear as wheals and quickly evolve to vesicles and initially appear as small “drops of water” or “dewdrops on a rose petal”- pathognomonic, superficial and thin-walled with surrounding erythema. • Vesicles become umbilicated and rapidly evolve to pustules and crusts over an 8- to 12-h period.

• With subsequent crops, all stages of evolution may be noted simultaneously, i.e., papules, vesicles, pustules, crusts, i.e., polymorphic.• Crusts fall off in 1–3 weeks, leaving a pink, somewhat depressed base.• Characteristic punched-out permanent scarsmay persist.• Uncommonly, hemorrhage into pustular lesion occurs in otherwise healthy children, i.e., hemorrhagic varicella

Distribution First lesions begin on face and scalp, spreading inferiorly to trunk and extremities.• Most profuse in areas least exposed to pressure,i.e., back between shoulder blades, flanks, axillae, popliteal and anticubital fossae• Density highest on trunk and face, less on extremities• Palms and soles usually sparedMucous Membranes Vesicles (not oftenobserved) and subsequent shallow erosions (2–3 mm)• Most common on palate• Mucosa of nose, conjunctivae, pharynx, larynx,trachea, GI tract, urinary tract, vagina

• ComplicationsSuper infection by methicillin-sensitive S . aureus (MSSA), methicillin-resistant S . aureus (MRSA), or GASImpetigo, furuncles, cellulitis, and gangrene • In children 5–11 years of age, the most common

complications are varicella encephalitis and Reye syndrome.

• In adults, prodromal symptoms are common and may be severe;Exanthem may last for a week or more, with prolonged period of recovery. • The mortality rate in adults was 15 per 50,000 cases (U.S.); 25% of varicella associated deaths did occur in adults.

Primary varicella pneumonia, which presents 1–6 days after appearance of rash, is relatively common in adults: 16% of adults show x-ray evidence of pneumonitis, but only 4% have clinical signs of pneumonitis. Women have a10% risk of severe VZV pneumonitis.VZV encephalitis may also complicate varicellain adults.• Less common complications of varicella include viral arthritis, uveitis, conjunctivitis, carditis, systemic inappropriate antidiuretic hormone syndrome(SIADHs), nephritis, and orchitis.• Maternal varicella during the first trimester ofpregnancy:

Fetus: Fetal varicella syndrome (limb hypoplasia,eye and brain damage, skin lesions) in 2% of exposed fetuses.Neonatal varicella has higher associated incidence of pneumonitis and encephalitis than occurs in older children.• Immunocompromised or glucocorticoid treatedpatients with varicella may manifest dissemination, hepatitis, encephalitis, and hemorrhagic complications.• If varicella occurs at an early age when maternalantibody is still present, an individual canhave a second episode of varicella.

DIAGNOSISUsually made on clinical findings alone.

MANAGEMENTPreventionImmunization VZV immunization is now available (Varivax) and is 80% effective in preventing symptomatic primary VZV infection. Those at high risk for varicella, who should be immunized, include: normal VZV-negative adults, children with leukemia, and immunocompromised individuals (immunosuppressive treatment, HIVinfection, cancer).

Symptomatic therapyLotions Directed at reducing pruritus.Oral antihistamines Application gives short-term relief of pruritus.Caution for antipyretic agents Antipyretic administration is of concern because of a possible link between aspirinand Reye syndrome in children with varicella. Antiviral agentsOtherwise healthy patients If begun within 24 h after onset of varicella, decreases the severity of varicella andreduces secondary cases.Acyclovir 20 mg/kg (800 maximum) four times daily for ∗5 daysValacyclovir Effective but not an approved use; dosing same as for herpes zoster.

Polymorphic lesion

Small pox virus• Monomorphic lesion

HERPES ZOSTER

HERPES ZOSTER (HZ)

• An acute dermatomal infection associated with reactivation of VZV

• Characterized by Unilateral pain• A vesicular or bullous eruption limited to a dermatome(s) innervated by a corresponding sensory ganglion.

EPIDEMIOLOGYAge of Onset More than 66% are >50 years ofage; 5% of cases in children <15 years HIV/AIDSIncidenceIn one cohort, 5% of individuals with HZwere HIV-infected and 5% had cancer.Recurrent HZ < 1% of cases Occurs in 25% of HIV-infected individuals, an eight times higher incidence than the general population, ages 20–50 years;

• Renal and cardiac transplant recipients:7–9%• Recurrent HZ more common in immunocompromisedindividuals.• Immunization to VZV in childhood will alterthe epidemiology of HZ.

Risk Factors• Most common factor is diminishing immunityto VZV with advancing age, with mostcases occurring in those ≥55 years.• However, in most cases triggering factors arenot known.• Immunocompromise: MalignancyImmunosuppression, especially from lymphoproliferativedisorders and chemotherapy Radiotherapy.HIV/AIDS: eightfold increased incidence of HZ.

Pathogenesis• In varicella VZV passes from lesions in the skin and mucosa via sensory fibers centripetally to sensory ganglia.• In the ganglia the virus establishes lifelonglatent infection.• Reactivation occurs in those ganglia in which VZV has achieved the highest density and is triggered by immunosuppression, trauma, tumor, or irradiation (see risk factors).• Reactivated virus can no longer be contained.• Virus multiplies and spreads antidromically down the sensory nerve to the skin/mucosa where it produces the characteristic vesicles

Classification: HZ manifests in three distinct clinical stages: prodrome, active infection,chronic: postherpetic neuralia (PNH). CLINICAL MANIFESTATIONSDuration of Symptoms• Prodromal stage: Neuritic pain or paresthesiaprecedes for 2–3 weeks (84% of cases).• Acute vesiculation: 3–5 days.• Crust formation: days to 2–3 weeks.• PHN: months to years. Chronic pain or PHN is that persisting after the lesions have healed or persisting 4 weeks after the onset of lesions, regardless of degree of healing.

Skin SymptomsProdromal Stage• Pain (stabbing, pricking, sharp, boring, penetrating,lancinating, shooting), tenderness,paresthesia (itching, tingling, burning, freeze burning)in the involved dermatome precedes the eruption. • Allodynia: heightened sensitivity to mildstimuli.Active Vesiculation Skin lesions may be pruriticbut in themselves are not painful.Zoster Sine Zoster Nerve involvement canoccur without cutaneous zoster.

Abdominal Zoster Presents with severeabdominal (or chest pain) that may precederash by hours to days.Chronic Stages PHN, described as “burning,”“ice-burning,” “shooting,” or “lancinating,” canpersist for weeks, months, or years after thecutaneous involvement has resolved. Constitutional Symptoms• Prodromal stage and active vesiculation: flulikesymptoms such as headache, malaise,fever.• Chronic stages: depression is very common inindividuals with PHN.

Mucocutaneous Lesions• Papules (24 h) → vesicles-bullae (48 h) → pustules (96 h) → crusts (7–10 days).• New lesions continue to appear for up to1 week.• Erythematous, edematous base (Fig. 27-42) with superimposed clear vesicles, sometimes hemorrhagic.• The vesicle-bulla is oval or round, may be umbilicated.• Vesicles erode forming crusted erosions Necrotic and gangrenous lesions sometimes occur.• Scarring is common after healing of HZ

Distribution• Unilateral, dermatomal .• Two or more contiguous dermatomes may beinvolved.• Noncontiguous dermatomal zoster is rare.• Hematogenous dissemination to other skinsites in 10% of healthy individualsSite of Predilection Thoracic (>50%), trigeminal(10–20%), lumbosacral and cervical (10–20%).Mucous Membranes Vesicles and erosionsoccur in mouth, vagina, and bladder, dependingon dermatome involved.

General ExaminationLymphadenopathy Regional nodes draining the area are often enlarged and tender.Sensory or Motor Nerve Changes Detectable by neurologic examination. Sensory defects(temperature, pain, touch) and (mild) motor paralysis, e.g., facial palsy. Eyes• In ophthalmic zoster, nasociliary involvement of V-1 (ophthalmic) branch of the trigeminal nerve occurs in about one-third of cases and is heralded by vesicles on the side and tip of the nose.• Complications include uveitis, keratitis, conjunctivitis,retinitis, optic neuritis, glaucoma,

proptosis, cicatricial lid retraction, and extraocular muscle palsies.• Acute retinal necrosis (rapidly progressive herpetic retinal necrosis) is more common in the immunocompromised hostDelayed Contralateral Hemiparesis• Occurs weeks to months (mean, 7 weeks) after an episode of HZ involving the first division of the trigeminal nerve (V-1).• Typical presentation is headache and hemiplegiaoccurring in a patient with recent history of HZ ophthalmicus.

thoracic zoster A 39-year-old female with HIV/AIDS hashad painful chest lesions for 3 weeks. Crusted and reepithelialized dermatomal erosions on the left back

Varicella zoster virus infection: disseminated cutaneous, in an immunocompromisedpatient

Varicella zoster virus infection: chronic herpes zoster in HIV disease

COURSE AND PROGNOSISIn immunocompetent host, rash usually resolves in 2 to 3 weeks. Complications can be:• Mucocutaneous Hemorrhage, gangrene Cutaneous dissemination Superinfection of skin lesions• SystemicNeurologic: meningoencephalitis, cerebral vascular syndromes, cranial nerve syndromes [trigeminal (ophthalmic) branch (HZ ophthalmicus), facial and auditory nerves (Ramsay Hunt syndrome)], peripheralmotor weakness, transverse myelitis

MANAGEMENTPreventionImmunization: Immunization with VZV vaccine may boost humoral and cell-mediated immunity and decrease the incidence of zoster in populations with declining VZV-specific immunity. Goals of management: Relieve constitutional symptoms; minimize pain; reduce viral shedding; prevent secondary bacterial infection; speed crusting of lesions and healing; ease physical, psychological, emotional discomfort; prevent viral dissemination or other complications; prevent or minimize PHN.

Antiviral therapy In individuals at high risk for reactivation of VZV infection, oral acyclovir can reduce the incidence of HZ. In prodromal stage: begin antiviral agent if diagnosis isconsidered likely; analgesics. With active vesiculation: antiviral therapy begun ≤72 h accelerates healing of skin lesions, decreases the duration of acute pain, and may decrease the frequency of PHN when given in adequate dosage.

Acyclovir 800 mg PO four times daily for 7–10 days. The 50% viral inhibitory concentration of acyclovir is three to six times higher for VZV than for HSV in vitro, and drugdose must be increased appropriately. The bioavailability of acyclovir is only 15–30% of the orally administered dose. For ophthalmic zoster and HZ in the immunocompromised host, acyclovir should be given intravenously. Acyclovir hastens healing and lessens acute pain if given within 48 h of the onset of the rash.∗Valacyclovir 1000 mg PO three times daily for 7 days, 70–80% bioavailable.

Famciclovir 500 mg PO three times daily for 7 days, 77% bioavailable. Reduce dose inindividuals with diminished renal function. Supportive therapy: for acute HZConstitutional symptoms Bed rest, nonsteroidal anti-inflammatory drugs.Sedation Pain often interferes with sleep. Sleep deprivation and pain commonly result indepression. Doxepin, 10–100 mg at bed time, is an effective agent.

Dressings Application of moist dressings (water, saline, Burow solution) to the involveddermatome is soothing and alleviates pain.Pain management Early control of pain with narcotic analgesics is indicated; failure to manage paincan result in failure to sleep, fatigue, and depression: Best to begin with more potent analgesics and then reduce potency as pain lessens.

Chronic stages (PHN)Pain management Pain is that of reflex sympathetic dystrophy. Severe prodromal pain or severe pain on the first day of rash is predictive of severe PHN.Gabapentin: 300 mg three times daily. Pregabalin.Tricyclic antidepressants such as doxepin, 10–100 mg PO at bed time.Capsaicin cream every 4 h.Topical anesthetic such as EMLA or 5% lidocaine patch for allodynia.Nerve block to area of allodynia.Analgesics.

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