Viral infection 2

Viral infection 2

Dr Anfal layth
arab board of dermatology

Other Clinical Presentations of HSV Infection

form of infection
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Eczema herpeticum

(Kaposi varicelliform
eruption)
• Occure in pt with atopic dermatitis and other skin disease with impaired skin barrier
• Rapid, widespread , Monomorphic, discrete, 2–3 mm punched-out erosions with hemorrhagic crusts
Herpetic whitlow
• Often in young children, usually due to HSV-1
• in dental and medical personnel who did not use gloves
• Pain, swelling, and clustered vesicles on a digit
Neonatal HSV
infection
• resulting from exposure to HSV during a vaginal Delivery( highest (30–50%) for primary skin lesion)
• Due to HSV-2 or HSV-1
• Onset from birth to 2 weeks of age
• Localized (favoring the scalp and trunk) or disseminated(different organ involvement)
• For CNS or disseminated disease, mortality is >50% withouttreatment and ~15% with treatment
•

Diagnosis:

1. Clinical.
2. Investigations:
Viral culture.
direct fluorescent antibody assays ,molecular techniques, and serology
A Tzanck smear of scrapings from early lesions, in particular the base/edges of a freshly unroofed vesicle, reveals multinucleated epithelial giant cells in ~60–75% of HSV outbreaks
Biopsy

Treatment:

* Mild:
1. Sun block.
2. Dabbing with spirit.
3. Topical antibiotics.

* Severe & frequent attacks
1. Acyclovir cream 5-6 times a day for 4 days.
2. Acyclovir tablet 200 mg 5 times daily for 5 days.
3. Famciclovir & valciclovir have additional advantage of needing fewer doses per day.


VARICELLA–ZOSTER VIRUS (VZV; HHV-3)
Infection with this virus will produce two clinical diseases:
1. Genenalized disease (Varicella or Chicken pox) in non-immune individuals.
2. Localized disease (Herpes Zoster) in partially immune individuals.

Chicken Pox (Varicella)

It is a highly contagious viral infection
The term “chickenpox” is thought to come from either the French word “chiche-pois” for chickpea (referring to the size of the vesicles)
VZV has a worldwide distribution and 98% of the adult population is seropositive.
Airborne droplets are the usual route of transmission of varicella, although direct contact with vesicular fluid is another mode of spread,

Pathogenesis

the incubation period is 11–20 days.
The affected individual is infectious from 1–2 days before skin lesions appear until all the vesicles have crusted
primary viremia occurs after an initial 2–4 days of viral replication within regional lymph nodes. A cycle of viral replication in the liver, spleen, and other organs is then followed by a secondary viremia, which seeds the entire body 14–16 days postexposure.
During this period, the virus enters the epidermis by invading capillary endothelial cells. VZV subsequently travels from mucocutaneous lesions to dorsal root ganglion cells, where it remains latent until reactivation at a later time.


Clinical Features
A prodrome of mild fever, malaise, and myalgia may occur, especially in adults.
This is followed by an eruption of pruritic, erythematous macules and papules, which starts on the scalp and face, and then spreads to the trunk and extremities .
Lesions rapidly evolve over ~12 hours into 1–3 mm clear vesicles surrounded by narrow red halos (“dew drops on a rose petal”).
there is often involvement of the oral mucosa
. Older vesicles evolve to form pustules and crusts, with individual lesions healing within 7–10 days.
The presence of lesions in all stages of development is a hallmark of varicella.

Complications:

1. Secondary infection.
2. Neurological complication: encephalitis, Reye's syndrome.
3. Pneumonia.
4. Hepatitis.
5. Scarring.
6. Hemorrhagic and lethal disease in immunocompromised.
Maternal varicella during the first 20 weeks of pregnancy is associated with a ~2% risk of congenital varicella syndrome (varicella embryopathy

Treatment and Prevention

Varicella
Varicella in immunocompetent children can be treated symptomatically with antipyretics (e.g. acetaminophen), antihistamines, calamine lotion, and tepid baths.
Oral acyclovir is FDA-approved for the treatment of varicella in adults as well as in children with chronic cutaneous or pulmonary disorders
Intravenous acyclovir is indicated for varicella in immunocompromised patients.

VZV vaccine

Approved by the FDA in 1995, the live attenuated VZV vaccine ( Varivax®) is highly efficacious, with seroprotection rates of ~85% after one dose and ≥99% after two doses in healthy children.
Two doses of the vaccine, routinely given at ages 12–15 months and 4–6 years, are recommended to improve protection and counteract

Herpes Zoster (Shingles)

Cutaneous viral infection involving the skin of a single dermatome.
People of all ages are affected, but it usually occurs in young adults and the incidence increases with age. The incidence of second attack is rare (<5%)
It results from reactivation of Varicella virus that entered the cutaneous nerves during an earlier episode of chicken pox.

Precipitating factors of reactivation:

1. Age.
2. Immunosupression( drug,disease).
3. Fatique.
4. Emotional upset.
5. Radiation.
Patient with zoster can transmit the virus and cause chicken pox in non-affected individuals.

Clinical presentation:

The attack usually starts with a burning pain or itching for 4-5 days, soon followed by erythema and grouped, sometime blood filled, vesicles scattered over a dermatome.
The clear vesicles quickly become purulent, after few days burst, and crust. Scabs usually separate in 2-3 weeks, sometime leaving depressed depigmented or hyperpigmented scar.
* Zoster characteristically is unilateral. It may affect more than one adjacent dermatome.
* The thoracic segment and ophthalmic division of trigeminal nerve are more commonly affected.
* Generalized chicken pox-like eruption with segmental zoster may occur in cases of immunosuppression and malignancy

Complications:

1. Secondary bacterial infection.
2. Motor nerve involvement.
3. Ophthalmic nerve lesion can lead to corneal ulcer and scarring.
4. Persistent neurological pain (post herpetic neuralgia).
5. Disseminated lesions.
6. Encephalitis.

Treatment

For herpes zoster, beginning antiviral treatment within 72 hours of the development of skin lesions

Acyclovir, famciclovir, and valacyclovir are all FDA-approved for the treatment of herpes zoster in immunocompetent individuals and result in decreased severity and duration of both skin lesions and pain .

Intravenous acyclovir is indicated for the treatment of zoster in immunocompromised patients as well as those with serious complications
- If diagnosis late, systemic antiviral is not effective and treatment is supportive: Rest, Analgesic and Antibiotics.


Post herpetic neuralgia: carbamazepine, amitriptyline, capsaicin cream.

Vaccination

the varicella vaccine was studied as a method of prophylaxis for herpes zoster.
vaccination increased immunity against VZV in elderly patients, 67% decrease in the likelihood of postherpetic neuralgia in vaccine recipients.
These results led to FDA approval of this live attenuated vaccine (Zostavax®) for adults ≥50 years of age
It is not indicated as a treatment for active herpes zoster or postherpetic neuralgia.

POXVIRUS INFECTIONS

The family Poxviridae are large, brick- or ovoid-shaped, double-stranded DNA viruses that are characterized by cytoplasmicreplication

Orf (ecthyma contagiosum, contagious pustular dermatosis, infectious pustular dermatitis)

Virus/genus Orf/ Parapoxvirus
Host Sheep, goats,reindeer,humans
Endemic in sheep and goats
At-risk occupations: shepherds, butchers, veterinary surgeons, sheepshearers

Clinical feature

The incubation period 1 week
lesion may be single or multiple
Start as Papules (1 to few) on hands at sites of contact with infected animals
• Progression through several stages:
- maculopapular
- targetoid
- weeping nodule
- regenerative dry stage with black dots
- papillomatosis
regression with a dry crust

• May be accompanied by lymphangitis,

lymphadenopathy, malaise, fever

Complication:

1. secondary infection.
2. Lymphadenitis and malaise.
3. Erythema multiforme in 5% of the cases.
4. Giant lesion can occur in immunocompromized.

Treatment:

Spontaneous healing.
Topical antibiotic to prevent secondary infection.
Shave excision may accelerate healing
Topical imiquimod may stimulate early regression; usually heals without scarring

Molluscum contagioseum

The MC virus (MCV) is a member of the Molluscipox genus of Poxviridae
MC is a common, self-limited condition in children.
It also occurs in adults, usually as a sexually transmitted disease
in immunocompromised hosts, most notably HIV-infected individuals may presented as giant type
Transmission is via skin-to-skin contact and, less commonly, fomites and sexual.


Clinical feature
The incubation period range from 2-6 weeks, often several members of one family are affected

The site of the lesion:

* Children: face, trunk, axilla and extremities.
* Adults: pubic and genital area (STD).*

The lesions

may be few or many
the palm and sole are not affected.
The individual lesions begin as smooth, shiny, white or pink, dome-shaped papule.
They grow slowly up to 0.5 cm, with time the center become soft and umblicated and may contain a cheesy core.
It is not uncommon to see erythema and scaling at the periphery of the lesions, which result from inflammation by scratching or hypersensitivity reaction.

Differential Diagnoses:

1. Inflammed lesion can simulate boil.
2. Large solitary lesion simulates keratoacanthoma.
3. Intradermal nevus.
4. Cystic BCC.
5. Warts

Treatment:

* Most lesions are self limiting and clear spontaneously in 6-9 months.
* Treatment must be individualized.
* Conservative non-scaring methods shoule be used in children.
* Genital lesion should be treated to prevent sexual spread.
1. Squeezing with forceps or piercing.
2. Curettage.
3. Cryotherapy.
4. Imiquimod cream.
5. Podophyllotoxin 0.5%.
6. Tretinoin 0.025- 0.01%.
7. Salicylic acid.
8. TCA.