Dermatology 5th year, 2nd lecture (Dr. Ali El-Ethawi)
Viral diseases of the skin &mucous membrane
DR. Ali El-ethawi
M.B.CH.B , F.I.C.M.S, C.A.B.D
Viruses are not cellular organism because they do not have
functional ribosome's or other cellular organelles,
i.e; obligate intracellular parasite because their replication depend
on host cell
Viral genome consist of only single type of nucleic acid (RNA ,DNA)
Two main groups of viruses are distinguished: DNA and RNA.
DNA virus types are herpesvirus, poxvirus ,parvovirus,
papovavirus and adenovirus.
RNA viruses are picornavirus, coronavirus paramyxovirus,
orthomyxovirus, togavirus, reovirus, retrovirus, arenavirus and
Some viruses are distinguished by their mode of transmission:
arthropod-borne viruses, respiratory viruses, fecal-oral or intestinal
viruses, venereal viruses, and penetrating wound viruses.
Viral infections of skin and mucosa produce a wide
spectrum of clinical manifestations.
Some Viruses not causing any clinical lesions.
(produce latent, but lifelong infection)
Some cause benign epithelial proliferations, i.e.,
Some viruses cause febrile illness with exanthems.
In the setting of immunocompromise, these viruses
can become active and cause disease with
significant morbidity and mortality rates.
•are medium-sized viruses dsDNA replicate in the cell nucleus.
•produce latent, but lifelong infection by infecting immune cells
•Intermittently have replicative episodes with amplification of the
viral numbers in anatomic sites from one host to the next (genital
skin, orolabial region).
The vast majority of infected persons remain asymptomatic.
Viruses in this group are ;
herpes simplex virus (HSV)1,2
varicella zoster virus (VZV)
Epstein-Barr virus (EBV)
Human herpesviruses (HHV)-6, -7, and -8
Herpesvirus simiae (B virus)
Herpes simplex viruses (HSV)
are common human DNA viral pathogens that intermittently
The virus is ubiquitous and carries continue to shed virus
particles in their saliva &tears.
There are two types of HSV: HSV-1 and HSV-2.
HSV-2 usually causes genital infection, whereas HSV-1 is mostly
are extragenital ,but both can infect oral and genital areas.
cause acute and recurrent infections.
Most of the adult population is seropositive for HSV-1, and the
majority of infections are acquired in childhood while acquisition
of HSV-2 correlates with sexual behavior.
HSV infections are classified as either primary “(first episode )“
1. primary infections
It is often asymptomatic or not recognized in most cases,
but they can also cause severe disease as
acute gingivostomatitis ;
is the recognizable manifestation of primary type-1 infection in children.
The onset is often accompanied by
high fever, malaise and cervical lymphadenopathy,.
The herpetic lesions in the mouth are usually broken vesicles
that appear as erosions or ulcers covered with a white membrane.
The erosions may become widespread on the
oral mucosa, tongue, and tonsils.,
The duration is 1 to 2 weeks.
Primary type -2 virus infection Usual transmitted sexually
often asymptomatic or , cause multiple & painful
Genital & perianal blisters which rapidly ulcerate
Most recurrences are not symptomatic (asymptomatic shedding), with
most transmissions occurring by asymptomatic shedding.
These strike in roughly the same place each time .They may ppt. by
RTI, UVR ,menstruation or even stress
Common site face ,lips (HSV-1) and the genitals (HSV-2) But lesions
can occur any where .
HSV can also cause diseases involving the eye, central nervous
system, and neonatal infection. Cellular immunity defects are a
risk factor for severe and disseminated disease.
Genital herpes ;is the most prevalent sexually transmitted disease
worldwide and is the most common cause of ulcerative genital disease,
and it is an important risk factor for acquisition and transmission of
human immunodeficiency virus. is spread by skin-to-skin contact,
usually during sexual activity. The incubation period averages 5 days.
Active lesions of HSV-2 contain live virus and are infectious .
Herpetic Whitlow Herpes simplex of the fingertip
HSV infection may uncommonly occur on the fingers or periungually.
Herpes Gladiatorum ; Cutaneous herpes, HSV-1 infection is highly
contagious occur in athletes involved in contact sports is transmitted via
direct skin-to-skincontact. This is a recognized health risk for wrestle
1.Eczema herpeticum (Kaposi's varicelliform eruption)
2. Recurrent Erythema multiforme
3. Disseminated herpes simplex
4.Herpes encephalitis or meningitis
5. Herpes simplex infection of the eye can cause recurrent dendritic
ulcer leading to corneal scarring
Diagnosis; depending on the clinical presentation and no need for
investigation ( Direct Microscopy (tzanck smear) ,viral culture, polymerase
chain reaction and serology).
Regimens and dosages vary with the clinical setting
by acyclovir, valacyclovir, or famciclovir.
Resistance is rare in other than immunocompromised patients.
Recurrence can be prevented by long term of treatment at lower dose
Varicella-Zoster Virus Infections (VZV)
It is a human herpes virus that infects 98% of adult populations.
Primary VZV infection (varicella or chickenpox) is nearly always
characterized by disseminated pruritic vesicles.
During primary infection, VZV establishes lifelong infection in
When immunity to VZV declines, VZV reactivates within the
nerve cell, traveling down the neuron to the skin, where it erupts
in a dermatomal pattern [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.
Varicella is the highly contagious primary infection
caused by varicella-zoster virus.
It is characterized by successive crops of pruritic
vesicles that evolve to pustules, crusts, and occur at
the same times, scars.
This infection is often accompanied by mild
the primary infection occurring in adulthood may be
complicated by pneumonia and encephalitis.
Incubation Period;14 days (range, 10 to 23 days).
Prodrome; Characteristically absent or mild. Uncommon in children,
more common in adults: headache, general aches and pains, severe
backache, malaise. Exanthem appears within 2 to 3 days.
In most children, illness begins with appearance of exanthem, vesicular
lesions evident in successive crops.
Often single, discrete lesions or scanty in number in children and much
more dense in adults.
Initial lesions are papules (often not observed) quickly evolve to vesicles
and initially appear as small "drops of water "on a rose petal" .
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.
Secondary bacterial Skin infection.; it is the most common
complication in children .
Neurologic complications. Encephalitis and Reye's syndrome
are complications of chickenpox.
Reye's syndrome is an acute, noninflammatory encephalopathy
associated with hepatitis or fatty metamorphosis of the liver; 20%
to 30% of Reye's syndrome cases preceded by varicella. The
fatality rate is 20%.
Salicylates used during the varicella infection may increase the
risk of the development of Reye's syndrome.
Pneumonia.; Pneumonia is rare in normal children, but it is the
most common serious complication in normal adults.
Herpes zoster (HZ) ,Shingles
is an acute dermatomal infection associated with reactivation of endogenous VZV that
had persisted in latent form within sensory ganglia after an earlier attack of varicella
Age of Onset; More than 66% are >50 years of age; 5% of cases in children <15
Pre eruptive pain (preherpetic neuralgia), unilateral, dermatomal, precedes the
eruption by 4 to 5 days.
Prodromal symptoms may be absent, particularly in children.
ERUPTIVE PHASE. The eruption begins with red, swollen plaque of varying sizes
and spreads to involve part or all of a dermatome
The vesicles arise in clusters from the erythematous base and become cloudy with
purulent fluid by day 3 or 4.
Successive crops continue to appear for 7 days.
Vesicles either umbilicate or rupture before forming a crust, which falls off in 2 to 3
The elderly or debilitated patients may have a prolonged and difficult course.
The major morbidity is postherpetic neuralgia (PHN).
The aim of treatment is the suppression of inflammation, pain, and
Oral antiviral agents are recommended in all patients over 50 with
pain in whom blisters are still present, even if they are not given
within the first 96 h of the eruption.
Antiviral therapy and analgesics aid acute pain control;
lidocaine patch (5 %), gabapentin, pregabalin, opioids, and tricyclic
antidepressants reduce postherpetic neuralgia
Oral analgesia should be maximized using acetaminophen,
nonsteroidal anti-inflammatory drugs (NSAIDs), and opiate analgesia
Local anesthetics, such as 10% lidocaine in gel form, 5% lidocaine-
prilocaine, or lidocaine patches (Lidoderm), may acutely reduce pain.
Gabapentin starting at 100 mg three times
Exanthems were previously consecutively numbered according to
their historical appearance
Diseases that begin with exanthems may be caused
by bacteria, viruses, or drugs
1. first disease, measles;
2.second disease, scarlet fever; (bacterial)
3.third disease, rubella;
4. fourth disease, "Dukes' disease" (probably
coxsackievirus or echovirus);
5.fifth disease, erythema infectiosum;
6.sixth disease, roseola infantum
Measles is a highly contagious childhood viral infection.
Significant morbidity and mortality occur in acute and chronic course.
Childhood immunization by combined MMR vaccine is highly effective at preventing infection.
Epidemic disease; worldwide distribution.
Etiology; Measles virus which is RNA paramyxovirus
Incubation Period;10 to 15 days.
Prodromal symptoms ;Fever, malaise, conjunctivitis,,photophobia ,URT catarrh ( coryza,
cough), Koplik spots ;Pathognomonic. Appear before exanthem.( Cluster of tiny bluish-white
spots on red background, on buccal mucosa opposite premolar teeth).
exanthem ;Generalized erythematous macules and papules that spread from the forehead
and behind the ears to the trunk and extremities; begins to fade in 4 to 5 days.
More severe disease in immunocompromised or malnourished individuals.
Treat secondary infections
Immune globulin, IM
German measles( RUBELLA)
Epidemic disease; worldwide distribution.
Cause; is an enveloped RNA virus in the Togaviridae family
Incubation period ;about 18 days
Short prodrome; pink macular rash ,which fades ,first on the turnk
over the course of few days.
Enlargement of cervical, suboccipital, and postauricular glands.
rubella during the first trimester carries high risk of fetal
malformations with congenital infection (microcephaly, congenital
heart disease, deafness).
Prevention by vaccination with the combined MMR vaccine
is caused by the B19 parvovirus.
It is relatively common and mildly contagious
appears sporadically or in outbreaks, often in the spring.
children between 5 and 14 years of age.
Incubation period; is 13 to 18 day
Asymptomatic infection is common.
Prodromal; Symptoms are usually mild or absent.
ERUPTIVE PHASE. There are three distinct, overlapping stages.
Facial erythema ("slapped cheek").
Reticular erythema of the shoulder.
Recurrent phase. The eruption may fade and then reappear in previously affected
sites on the face and body during the next 2 to 3 weeks.
(Papular acrodermatitis of childhood)
Common, self-limited dermatosis.
presenting as discrete non-pruritic, erythematous monomorphic
dome-shaped or flat-topped papules symmetrically distributed on
face, buttocks and extensor extremities.
Typically, the trunk is spared
Associated with multiple viral triggers and immunizations.
Historically associated with hepatitis B infection, but now more often
triggered by Epstein-Barr virus.
The exanthem occurs in children 1 to 6 years old,
Duration is 2 to 3 weeks.
Roseola Infantum (Exanthem Subitum, Sixth Disease)
a common cause of sudden, unexplained high fever in young children
between 6 and 36 months of age.
Prodromal fever is usually high and convulsions and lymphadenopathy may
Suddenly, on about the fourth day, the fever drops.
a morbilliform erythema consisting of rose-colored discrete macules
sites ; the neck, trunk, and buttocks, and sometimes on the face and
The eruption may also be papular or, rarely, even vesicular.
The mucous membranes are spared.
Complete resolution of the eruption occurs in 1 to 2 days.
Human Papillomavirus Infections (HPV)
are very widespread-to-ubiquitous in humans,
causing subclinical infection or a wide variety of
benign clinical lesions on skin and mucous
They also have a role in the oncogenesis of
cutaneous and mucosal premalignancies
[squamous cell carcinoma (SCC) and SCC in situ
(SCCIS)] and malignancies (invasive SCC).
More than 150 types of HPV have been identified
and are associated with various clinical lesions and
Transmission; Skin-to-skin contact.
Other Factors; Immunocompromise, such as occurs in HIV disease or after iatrogenic
immunosuppression with solid organ transplantation, is associated with an increased incidence of and
more widespread cutaneous warts. Occupational risk associated with meat handling.
Duration of Lesions; Warts often persist for several years if not treated.
Symptoms; Cosmetic disfigurement. Plantar warts act as a foreign body and can be quite painful during
normal daily activities such as walking if located over pressure points.
More aggressive therapies such as cryosurgery often result in much more pain than that caused by the
wart itself. Bleeding, especially after shaving.
Verruca Vulgaris (Common Warts)
Firm papules, 1 to 10 mm or rarely larger , hyperkeratotic, clefted surface, with vegetations. Palmar
lesions disrupt the normal line of fingerprints. Return of fingerprints is a sign of resolution of the wart.
Characteristic "red or brown dots" are better seen with hand lens and are pathognomonic, representing
thrombosed capillary loops.
Isolated lesion, scattered discrete lesions. Annular at sites of prior therapy. Occur at sites of trauma:
hands, fingers, knees. Butcher's warts: large cauliflower-like lesions on hands of meat handlers.
Filiform warts have relatively small bases, extending out with elongated cap.
Common warts (Verruca
first begin as smooth, flesh colored papules,
lesion enlarge into dome-shaped, gray-brown irregular growths with
rough hyperkeratotic surface, studded with brown-black dots
(thrombosed capillaries). are a useful diagnostic sign
The hands are the most commonly involved areas,
but warts may be found on any skin surface.
They are more often multiple than single
Pain is rare
Aims of therapy are
1) to remove the wart;
2) not toproduce scarring;
3) to induce lifelong immunity to prevent recurrence.
Cryotherapy is a reasonable first line therapy for most common warts.
Products containing salicylic acid with or without lactic acid
Simple occlusion with a relatively impermeable tape can be effective in
Surgical destruction with cautery or ablation of warts can be effective treatment,
but even complete destruction of a wart and the surrounding skin does not
guarantee the wart will not recur. for warts that are refractory
Bleomycin has high efficacy and is an important treatment for
recalcitrant common warts.
plane Warts (Verruca Plana)
Sharply defined, flat papules (1 to 5 mm); "flat"
surface, skin-colored or light brown.
Round, oval, polygonal, linear lesions (inoculation
of virus by scratching).
There may be only a few, but in general they are
numerous & painless
Lesions that arise after trauma may have a linear
Occur on face (,forehead , about the mouth) , the
backs of the hands, beard area, shins.
Flat warts frequently undergo spontaneous remission, so therapy
should be as mild as possible, and potentially scarring therapies should
Treatment with topical tretinoin
Tazarotene cream or gel may also be effective If lesions are few, light
cryotherapy is a reasonable consideration.
Imiquimod 5 % cream used up to once a day can be effective.
5-FU cream 5%
applied twice a day may be very effective.
For refractory lesions, laser therapy in very low fluences or
might be considered before electrodesiccation because of the reduced
risk of scarring.
Warts of the soles are called plantar warts .
These have a rough surface which
protrude only slightly from the skin & surrounded
by bony collar .
On paring , the presence of the bleeding
capillary loops allows planter warts to be
distinguish from corns .
Often multiple .
It can be painful
A cluster of many warts that appears
to fuse is referred to as amosaic wart
In general, plantar warts are more refractory to any form of treatment
than are common warts.
Initial treatment usually involves daily application of salicylic acid in
liquid, film, or plaster form after soaking.
In failures, cryotherapy or cantharidin application may be attempted,
alone or in combination.
A second freeze-thaw cycle is beneficial when treating plantar warts
Bleomycin injections, laser therapy, or topical immunotherapy, may be
used in refractory cases.
Surgical destruction with cautery or blunt dissection should be reserved
for failures with nonscarring techniques, since a plantar scar may be
CO2 laser may also result in plantar scars.
Genital warts are the most common STD Among sexually-active young adults in
the US and Europe,
are pale pink with numerous, discrete, narrow-to-wide projectionson a broad base.
The surface is smooth or velvety, moist, and lacks the yperkeratosis of warts found
Can appear any where in genital area .
The warts may coalesce to form a large, cauliflower-like masses in moist,
occluded areas such as the perianal skin, vulva, and inguinal folds.
Another type is seen most often in young, sexually active patients. Multifocal,
often bilateral, red- or brown pigmented slightly raised, smooth papules .
The presence of anogenital warts in children raise the spectra of sexual
abuse ,but is usually caused by auto inoculation from common wart elsewhere
Because no effective virus-specific agent exists for the treatment of genital warts, their recurrence is
Podophyllin is more effective in treating warts on occluded or moist surfaces, such as the mucosa or
under the prepuce. as a crude extract, usually in 25 % in tincture of benzoin.
Purified podophyllotoxin 0.5% solution or gel is applied by the patient twice a day for 3 consecutive days
of each week in 4- to 6-week treatment cycles.
Imiquimod, an immune response modifier which induces IFN locally at the site of application,
Trichloroacetic acid (TCA) 35 % to 85 % weekly or biweekly. TCA is safe for use inpregnant patients.
Cryotherapy with liquid nitrogen
Electrofulguration or electrocauterization
The use of CO2 laser in the treatment of genital warts has not been demonstrated to be more effective
than simpler surgical methods.
Any surgical method that generates a smoke plume is potentially infectious to the surgeon.
5-FU 5% cream applied twice a day may be effective, 5-FU is not commonly recommended for the
treatment of typical external genital warts because other methods of
treatment are available.
The efficacy of systemic and intralesional IFN-a therapy has been
found to be relatively low in eradicating genital warts.
Molluscum contagiosum (MC), is a self-limited epidermal viral infection.
Etiology; a double-stranded DNA poxvirus , with 30% homology with smallpox virus.
Types MCV-1 and MCV-2.
Age, Sex; Children; sexually active adults; males > females.
Transmission ;Skin-to-skin contact. spreads via autoinoculation, scratching, or touching a lesion
clinically ; skin-colored papules that are often umbilicated, occurring in children and sexually
In HIV-infected individuals, however, numerous large mollusca often arise on the face, causing
significant cosmetic disfiguremen
Sites; most commonly involved are the face, trunk, axillae, extremities in children, and the pubic
and genital areas in adults
Unlike warts, the palms and soles are not involved
Classification by Risk Groups
Children;exposed skin sites. Child-to-child transmission relatively low. Resolve spontaneously.
Usually caused by MCV-1.
Sexually Active Adults; Occur in genital region. Virus transmitted during sexual activity. Resolve
HIV-Infected Individuals; Most commonly occur on the face, spread by shaving. Usually caused
Most lesions are self-limiting and clear spontaneously
in 6 to 9 months; however, they may last
2 to 4 years or longer.
Genital molluscum contagiosum may be
a manifestation of sexual abuse in children.
Treatment must be individualized.
Conservative non scarring methods should be used for children who have
many lesions. Genital lesions in adults should be definitively treated to
prevent spread by sexual contact .
Imiquimod (Aldara cream) ,
podophyllotoxin 0.5% (Condylox) ,
Tretinoin (Retin-A) cream ,
Salicylic acid (Occlusal)
Human Orf; Ecthyma contagiosum
Human orf ;
is a parapoxvirus infection that normally occurs in ungulates but occurs in
humans exposed to the virus; it is characterized by nodular lesions on
exposed cutaneous sites.
(hands, arms, legs, face); most common site is dorsum of right index finger.
Other Findings; Ascending lymphangitis and lymphadenopathy may occur.
Bacterial superinfection may occur.
More extensive infection may occur in the immunocompromised host
Course; lesion resolves spontaneously in 4 to 6 weeks, healing without scar
Management; Antiviral agents are not effective.
Treat bacterial superinfection; manage pain.