Viral Skin Infections - PowerPoint Presentation

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Viral Skin Infections

Presented by: Laith Sorour

Herpes Simplex Virus

Herpesvirus

hominis

is the cause. The virus is ubiquitous and carriers continue to shed virus particles in their saliva or tears.Two types:Type I Virus (HSV-1) : usually extragenital.Type II virus (HSV-2): mainly on the genitals.*however, this distinction is not absolute.Route of infection: mucous membranes abraded skin. After the episode associated with the primary infection, the virus may become latent, possibly within nerve ganglia, but still capable of giving rise to recurrent bouts of vesication (recrudescences).

Presentation

Primary

infection

:most common manifestation of a primary type I infection in children is an acute gingivostomatitisMalaise,

headache, fever

and enlarged cervical nodes.

Vesicles

, soon turning into

ulcers, seen scattered over the:LipsMucous membranes.The illness lasts about 2 weeks.Herpetic whitlowDirect inoculation (eg. During wrestling)Pus-filled blisters on a fingertip.Primary type IITransmitted sexuallyMultiplePainfulGenital or perianal blisters which rapidly ulcerate.

Recurrent (recrudescent) infections

Same place each time.

Precipitated

by

RTI (

cold sores

)

Ultraviolet

radiation

Menstruation

Stress

.

Common

sites

Face

Lips

(type I)

Genitals

(type II)

Lesions can occur anywhere.

Tingling, burning or

pain

is followed within a few hours by

Erythema

and

clusters

of tense

vesicles

.

Crusting

occurs within 24–48 h .

The whole episode lasts about

12 days

.

Complications

Herpes encephalitis

or

meningitisDisseminated herpes simplexEczema herpeticum: patients with atopic eczema are particularly susceptible to widespread cutaneous herpes simplex infections. Those looking after patients with atopic eczema should stay away if they have cold sores.Recurrent dendritic ulcers leading to

corneal scarring.Recurrent herpes simplex infections are regularly followed by

Erythema multiforme.

Investigations:

Culture

Antibody titres rise with primary, but not with recurrent infections.Treatment:SunblockDabbing with the surgical spiritTopical bacitracin, mupirocin, framycetin or fusidic acid (20 infection)Aciclovir cream ( applied 5-6X a day for the first 4 days of the episode)

More effective still is

oral

aciclovir 200 mg five times daily for 5 daysRecurrences in the immunocompromised can usually be prevented by long-term treatment at a lower dosage.

ECZEMA

 HERPETICUM

erythma

multiform

HPV

Warts are caused by the human papilloma virus.

Their prevalence is highest in childhood

.HPV-1, 2 and 4 are found in common warts. HPV-3 is found in plane warts. HPV-6, 11, 16 and 18 are most common in genital warts.Warts adopt a variety of patterns :

Common warts: The first sign is a smooth skin- coloured papule , often more easily felt than seen. usually occur on the hands ,face and genitals . They are more often multiple than single . Pain is rare.Plantar warts

: These have a rough surface, which protrudes only slightly from the skin and is surrounded by a horny collar . On paring, the presence of bleeding capillary loops allows plantar warts to be distinguished from corns . Often multiple , plantar warts can be painful.

Mosaic warts :

These rough

marginated plaques are made up of many small tightly packed but distinct individual warts. They are most common on the soles but are also seen on palms and around fingernails. Usually , they are not painful.Plane warts :These smooth flat-topped papules are most common on the face and brow, on the backs of the hands , and on the shaven legs of women. Usually skin-coloured or light brown, they become inflamed as a result of an immunological reaction, just before they resolve spontaneously . Lesions are multiple and painlessFacial warts: These are most common in the beard area of adult males and are spread by shaving. They are painless.Anogenital warts : Papillomatous cauliflower-like lesions,with a moist macerated vascular surface

Complications :

Some

plantar warts are very painful

Epidermodysplasia verruciformis (treeman syndrome) ARMalignant change is otherwise rare although infection with HPV types 16 and 18 predisposes to cervical carcinoma. HPV infections in immunocompromised patients have also been linked with skin cancer.

Treatment : Many warts give no trouble, need no treatment and go away by themselves. Otherwise, treatment will depend on the type of wart. Palmoplantar warts

: home treatment is best, with one of the many wart paints or plasters now available, Most contain salicylic acid No progress after regular correct use of salicylic acid Cryotherapy with liquid nitrogen , however its painful.

Anogenital

warts : self-treatment using podophyllotoxin or imiquimod , Two vaccines against HPV-6 and 11 are now available.

Facial common warts : These are best treated with electrocautery .Plane warts : On the face these are best left untreated and spontaneous resolution will occur.Solitary , stubborn or painful warts : These can be removed under local anesthetic with a curette or Bleomycin can also be injected into such warts .

Varicella (Chickenpox)

Cause

The herpes virus varicella-zoster is spread by the respiratory route; its incubation period is about 14 days.

Presentation and courseSlight malaise then papules, which turn rapidly into clear vesicles on a pink base (‘dew drops on a rose petal’).Vesicles soon become pustules and then umbilicate. Over the next few days the lesions crust and then clear, sometimes leaving white depressed scars. Lesions appear in crops, are often itchy and are most profuse on the trunk and least profuse on the periphery of the limbs (centripetal).Second attacks are rare. Varicella can be fatal in those who are immunologically compromised.Complications Pneumonitis, with pulmonary opacities on X-ray. Secondary infection of skin lesions. Haemorrhagic

or lethal chickenpox in patients with leukaemia and other immunocompromised children and adults.Scarring.Differential diagnosisSmallpox, mainly centrifugal anyway, has

been universally eradicated in 1980, and the diagnosis of chickenpox is seldom in doubt.InvestigationsNone are usually needed. The Tzanck smear is positive

.

Treatment

In mild attacks, calamine lotion topically is all that is required.Aciclovir, famciclovir and valaciclovir should be reserved for severe attacks and for immunocompromised patients; for the latter.Prophylactic aciclovir can also be used to prevent disease if given within a day or two of exposure. Alive attenuated vaccine is now available, and being more widely used. It is not universally effective and should not be given to patients with immunodeficiencies, therapeutic immunosuppression, or blood dyscrasias who might not be able to resist even the attenuated organism.

Herpes zoster (Shingles)

Caused

by the herpes virus varicella-zoster/HHV-3 (reactivation)

The incidence is high, when weaken normal defence mechanisms in:Old ageHodgkin’s diseaseAIDS

LeukaemiaShingles does not occur in epidemics

Patients with zoster can transmit the virus to others in whom it will cause chickenpox.

Presentation and course

Start with a

burning pain,

Soon followed by erythema and grouped.Sometimes blood-filled vesicles scattered over a dermatome

.The clear vesicles quickly become purulent

Over the space of a few days burst and crust.

Scabs usually separate in 2–3 weeks, sometimes leaving

depressed

depigmented scars.UnilateralIt may affect more than one adjacent dermatome.The thoracic segments and the ophthalmic division of the trigeminal nerve are involved disproportionoften.Generalized chickenpox-like eruption accompanying segmental zoster, particularly if the lesions are unusually haemorrhagic or necrotic, should raise suspicionsately of:Immunocompromised stateMalignancy`

Complications:

Secondary bacterial infection

is common.

Motor nerve involvement is uncommon, but has led to paralysis of ocular, facial muscles, diaphragm & bladder.Corneal ulcers and scarring (zoster of the ophthalmic division of the trigeminal nerve). A good clinical clue here is involvement of the nasociliary branch (vesicles grouped on the side of the nose).

Persistent neuralgic pain, after the acute episodeis

over, is most common in the elderly.DDx:

Pain

(before the rash has appeared)

Acute appendicitisMyocardial infarctionAn early painful red plaque may suggest cellulitisHerpes simplexEczemaImpetigoNOTE: THE DERMATOMAL DISTRIBUTION AND THE PAIN ALLOW ZOSTER TO BE DISTINGUISHED EASILY FROM HERPES SIMPLEX, ECZEMA AND IMPETIGO.Investigations:Cultures (only positive in 70%)Biopsy

or

Tzanck

smearsMultinucleated giant cellsBallooning degeneration of keratinocytesTreatment:

Systemic treatment (within the first 5 days)

Early: Famciclovir

and valaciclovirLate: (supportive)Systemic treatment is not likely

Rest

Analgesics

Calamine

Prevention (|vaccine) better than treatment

Orf

Contagious pustular dermatitis is common in

lambs

. Its cause is a parapox virus that can be transmitted to those handling infected animals. The incubation period is 5–6 days.Lesions, which maybe single or multiple, start as small firm papules that change into flat-topped apparently pustular nodules with a violaceous and erythematous surround The condition clears up spontaneously in a bout a monthComplicationsLymphadenitis and malaise are common. Erythema multiforme ‘Giant’ lesions can appear in the immunosuppressed

InvestigationsNone are usually needed. If

there is any doubt, the diagnosis can be confirmed by the distinctive electron microscopic appearance of the virus obtained from crusts.TreatmentTopical antibiotic helps to prevents secondary infection; otherwise no active therapy is needed.

Molluscum contagiosum

Cause

common pox virus infection which can be spread by direct contact (e.g. sexually or by sharing a towel at the swimming bath).Presentation and courseThe incubation period ranges from 2 to 6 weeks.Individual lesions are shiny, white or pink, and hemispherical they grow slowly up to 0.5 cm in diameter. A central punctum which may contain a cheesy core that gives the lesions their umbilicated look. On close inspection a mosaic appearance may be seen.Multiple lesions are common and their distribution depends on the mode of infection. Atopic individuals and the immunocompromised are prone to especially extensive infections.spread by scratching and the use of topical steroids.

Untreated lesions usually clear in 6–9 months, often after a brief local inflammation. Large solitary lesions may take longer. Some leave depressed scars.

Complications Eczematous patchessecondarily infected

Investigations

None are usually needed, but the diagnosis can be confirmed by looking under the

microscope for large swollen epidermal cells, easily seen in unstained preparations of the lesion.Treatment Treatment Many simple destructive measures cause inflammation and then resolution. They include squeezing out the and curettage.doing nothing is often the best option in children.Sometimes a local anaesthetic for an hour, will help children to tolerate more attacking treatmentSparse eyelid lesions can be left alone but patients with numerous lesions may need to be referred to an ophthalmologist for curettage.

Thank you

Resources:

Clinical dermatology 5

th editionPUBMED