Viral skin infections
Herpes simplex
• Caused by herpes virus hominis, DNA virus.
• HSV I: mostly oral, transmitted by saliva
• HSV II: mostly genital transmitted by sex
Virus entry ͢
attacks
primary infection ͢
latent infection ͢ recurrent
Clinical features
Primary type I: usually affects children
●Usually asymptomatic
● Few Symptomatic ͢
heals within 2 weeks
͢
gingivostomatitis-vesicles and erosions,
keratitis
͢ Whitlow, infection of the finger mostly in
children, transmitted from oral lesion due to finger sucking.
Primary type II: genital vesicles and painful erosions
Recurrent attacks (type I):
Herpes labilais or cold sore: Recurrent vesicles, then pustules and
erosions in the lips and near skin
Ppt. factors: sunlight, menstruation, viral and bacterial infections.
Recurrent attack usually last for 1 week.
Recurrent type II:
Recurrent genital ulcers affecting the penis, vulva, vagina and anus.
Type II recur more frequent than type I
It is a common STD
It represents a bad stigma with guilt feeling because of its persistence for
many years.
Complications
• Meningitis
• Encephalitis
• Disseminated inf.
• Secondary impetigo
• Corneal ulceration
Treatment
Primary:
●Mild cases: rest, symptomatic, acyclovir 200mg 5 times daily for 10 days.
●Disseminated inf. In immunocompromised : intravenous acyclovir 510mg/ kg 8 hourly
●Recurrent attacks: suppressive therapy, Acyclovir 400mg twice daily
Acyclovir not eradicates the HSV from the ganglia, but decrease the
recurrence
Varicella zoster
• Caused by reactivation of V-Z virus acquired from previous chicken
pox inf.
• V-Z virus latent in the cranial or dorsal root ganglia, its reactivation
herpes zoster at the dermatome of corresponding nerve
• Usually its risk increase with age and low immunity
Clinical features
• Unilateral dermatomal pain for 3-5 days, then vesicles appear and
then ulcerations.
Last 2-6 weeks according to the age. Duration increases with age.
Sites of involvement: thoracic, cervical, trigeminal, lumbosacral
Complications
• Secondary bact. Inf.
• Corneal ulceration in ophthalmic zoster
• Motor nerve involvement
• Post herpetic neuralgia
Treatment
• Mild cases: rest, symptomatic
• Severe cases, opthalmic zoster, low immunity
acyclovir within 2-3 days
Viral warts
• Cause: HPV, more than 60 subtypes
• Transmission: direct contact and sex.
• Usually affects young people
• Immune deficiency predispose to extensive warts
• Type 16 and 18 cause cervical ca.
Clinical features
• Common warts ( verruca vulgaris): single or multiple papules with
rough surface.
Usually affect the hands, but can appear anywhere.
• Plantar warts: rough slightly raised papules.
• Plane warts: slightly raised skin colored- grey- pink smooth papules.
Face and hands
• Anogenital warts (condylomata acuminata): affects skin and mucous
membrane of the genital area.
Papillomatous or cauliflower lesions
It is similar to condylomata lata which are flat papules representing
secondary syphilis
Treatment
• Local therapy:
*Keratolytics: 12-20% salicylic acid
* Caustic agents: TCA for genital warts
* cytotoxics:
●5-FU for plane warts.
●podophylline for genital warts
* Surgical: curretage, electrocautery, cryotherapy
* immunomodulators: imiquimod for plane and genital warts
* Retinoic acid: for plane warts
Systemic therapy
• For extensive warts
• Zinc sulfate, BCG vaccine, retinoids.
Pox virus infections
Molluscum contagiosum
* Pox virus, transmitted by direct contact and sex
* Clinical features: I.P. 2-6 weeks
*Shiny white or pink papule with central punctum in some cases.
* Usually disease of children, especially affects the face.
* In adults involvement of the genital area indicates STD.
Treatment
• Squeezing, curretage, cryotherapy, cautery, phenol puncture, retinoic
acid
Orf
• Caused by parapox v.
• Transmitted from sheep.
• I.P. 5-6 days
• Firm papule then pustular nodule
• Clear in about 1 month spontaneously.
• No treatment required.
Measles
• Paramyxovirus, droplet transmission.
• I.P. 10 days
• Catarrhal stage:2 days of fever, running nose, red eyes, then
photophobia and koplik’s spots
• Days 3-4 maculopap. rash
• Days 6-7 days fever and rash decrease
Complications
• Pneumonia, keratitis, otitis media, encephilitis, weight loss
Treatment
Symptomatic, antibiotics for secondary bact. Inf.
Rubella (German measles)
• Caused by toga virus, droplet inf.
• I.P. 18 days.
• Less severe than measles, trivial in children, more sever in adults.
• Prodromal symptoms with suboccipital LAP
• Fine maculopap. Rash
Varicella
• V-Z virus.
• Prodromal symptoms
• Pink papules ͢vesicles ͢ pustules ͢ crusted erosions
• Cetripetal distribution
• Treatment: sympotmatic, acyclovir for adults, severe cases and
immunocompramised
AIDS
• Caused by HIV, which target the CD4 T cells
• Skin manifestations of AIDS
*Tumors: kaposi sarcoma, extensive with systemic involvement
* Dermatitis: seborrheic derm.
* Infections: opportunistic inf. ex candidiasis, severe HSV and HZV.