viral skin infection

Infectious DiseasesInfectious Diseases

Infectious DiseasesInfectious Diseases

Common Viral Skin DiseasesCommon Viral Skin Diseases Measles ( Rubeola)Measles ( Rubeola) Rubella (German Measles)Rubella (German Measles) Roseola Infantum (exanthem subitum)Roseola Infantum (exanthem subitum) Erythema Infectiosum (fifth disease)Erythema Infectiosum (fifth disease) Herpes SimplexHerpes Simplex Varicella (Chicken Pox)Varicella (Chicken Pox) Herpes Zoster (shingles)Herpes Zoster (shingles) Molluscum ContagiosumMolluscum Contagiosum WartsWarts

Infectious diseaseInfectious disease

Measles (Rubeola)Measles (Rubeola) Humans are the only natural host for measles Humans are the only natural host for measles

virus virus RNA containing, pleomorphic, enveloped RNA containing, pleomorphic, enveloped

paramyxovirus with a worldwide distribution.paramyxovirus with a worldwide distribution. measles is spread by direct contact with measles is spread by direct contact with

droplets of respiratory secretions. droplets of respiratory secretions.

measlesmeasles

The incubation period of measles is 10 to 14 The incubation period of measles is 10 to 14 daysdays

followed by a prodromal phase that followed by a prodromal phase that corresponds to the secondary viraemia.corresponds to the secondary viraemia.

The prodromal symptoms are cough, coryza, The prodromal symptoms are cough, coryza, conjunctivitis, fever and anorexia and conjunctivitis, fever and anorexia and normally last for 2-4 days. normally last for 2-4 days.

MeaslesMeasles

During this period the epithelium of the entire During this period the epithelium of the entire respiratory tract is inflamed and reddened and respiratory tract is inflamed and reddened and patients are at their most infectious: croup, patients are at their most infectious: croup, bronchiolitis and viral pneumonitisbronchiolitis and viral pneumonitis

Warthin finkeldey bodiesWarthin finkeldey bodies

MeaslesMeasles

Measles pneumonia. Histology showing mononuclear cells infiltration and multinucleate giant cells

measlesmeasles

Koplik's spots are found towards the end of the Koplik's spots are found towards the end of the prodrome and can still be seen during the first prodrome and can still be seen during the first two days of the skin eruption.two days of the skin eruption.

the enanthem can be seen as minute bluish the enanthem can be seen as minute bluish white spots on an erythematous base, varying white spots on an erythematous base, varying in number from a few to hundreds. The spots in number from a few to hundreds. The spots are best seen in the buccal groove at the level are best seen in the buccal groove at the level of the lower premolars.of the lower premolars.

they can sometimes be seen in the conjunctiva.they can sometimes be seen in the conjunctiva.

measlesmeasles

The minute white dots seen on the inflamed buccal mucosa are koplik’s spots

MeaslesMeasles

Measles, with koplik’s spot on the buccal mucosa. This is an unsually severe case, enough to cause considerable discomfort when feeding.

MeaslesMeasles

The measles rash appears first on the temples The measles rash appears first on the temples and behind the ears then spreads rapidly over and behind the ears then spreads rapidly over the face and down the body to involve the the face and down the body to involve the trunk and limbs (including the palms and trunk and limbs (including the palms and soles).soles).

Rash- is generalized, maculopapular, Rash- is generalized, maculopapular, erythematous and often somewhat purplish in erythematous and often somewhat purplish in tinge. Individual spots are irregular in shape tinge. Individual spots are irregular in shape and of variable size.and of variable size.

MeaslesMeasles

The rash often begins behind the ears. Koplik’s spots were visible on the buccal mucosa.

MeaslesMeasles

The rash is already prominent on the face and is spreading down the body onto the trunk and extremities

measlesmeasles

After a few days of uncomplicated measles, fever After a few days of uncomplicated measles, fever subsides and the rash fades at the same time.subsides and the rash fades at the same time.

Capillary leakage at the height of the illness is Capillary leakage at the height of the illness is revealed by transient purpura (post-measles staining) revealed by transient purpura (post-measles staining) in the distribution of the rash. in the distribution of the rash.

The common complications of measles are secondary The common complications of measles are secondary bacterial infections of the respiratory tract bacterial infections of the respiratory tract (particularly pneumonia and otitis media(particularly pneumonia and otitis media

MeaslesMeasles

During the healing phase, a transient brown staining of the skin maybe apparent in white children.

Rubella (German Measles)Rubella (German Measles)

Rubella virus, an enveloped RNA virus in the Rubella virus, an enveloped RNA virus in the Togaviridae family Togaviridae family

spread by droplets of respiratory secretions.spread by droplets of respiratory secretions. The large epidemics of infection that The large epidemics of infection that

previously occurred every 5-10 years have previously occurred every 5-10 years have been prevented in countries where vaccination been prevented in countries where vaccination is widespread. is widespread.

RubellaRubella

The incubation period of rubella averages 18 The incubation period of rubella averages 18 days with a range of 12-23 days.days with a range of 12-23 days.

The clinical features of rubella (notoriously) The clinical features of rubella (notoriously) vary from patient to patient.vary from patient to patient.

RubellaRubella

the lymphadenopathy may be generalizedthe lymphadenopathy may be generalized posterior cervical and suboccipital lymph nodes are posterior cervical and suboccipital lymph nodes are

characteristically enlarged.characteristically enlarged. It may last for several weeks.It may last for several weeks. The exanthem of rubella is a discrete, pink, diffuse, The exanthem of rubella is a discrete, pink, diffuse,

macular rash.macular rash. rash is most marked upon the face and trunk on the rash is most marked upon the face and trunk on the

first day then spreads peripherally along the limbs on first day then spreads peripherally along the limbs on the second day before disappearing on the third and the second day before disappearing on the third and fourth day.fourth day.

RubellaRubella

Although the rash is quite profuse, the elements are discrete except on the face, which shows general flushing.

RubellaRubella

A typical diffuse macular rash over the trunk.

RubellaRubella

Close up of the rash on the trunk.

RubellaRubella

There is no specific therapy for rubella.There is no specific therapy for rubella. Live vaccines are used in an attempt to prevent Live vaccines are used in an attempt to prevent

congenital rubella.congenital rubella. Other countries vaccinate girls as they Other countries vaccinate girls as they

approach puberty.approach puberty. Despite specific immunity, reinfection with Despite specific immunity, reinfection with

rubella virus is now known to occur.rubella virus is now known to occur.

Roseola infantum Roseola infantum (exanthem subitum)(exanthem subitum)

This disease of infants aged 6 months to 3 This disease of infants aged 6 months to 3 years.years.

Causative agent- Human Herpes Virus type 6 Causative agent- Human Herpes Virus type 6 (HHV-6)(HHV-6)

The incubation period is 10-15 days and there The incubation period is 10-15 days and there is usually no prodromal illness.is usually no prodromal illness.

Roseola infantumRoseola infantum

Human herpes virus type 6. Electro micrograph of extracellular, mature, enveloped HHV-6 virus budding from a cell.


Electro micrograph of HHV-6 capsids in a cell nucleus.


First symptom is high fever, sometimes with First symptom is high fever, sometimes with lymphadenopathy, and this lasts for a few days lymphadenopathy, and this lasts for a few days during which the child appears quite well.during which the child appears quite well.

As the fever resolves it is followed by a As the fever resolves it is followed by a maculopapular rash of central distribution maculopapular rash of central distribution which itself lasts for a few hours to a few dayswhich itself lasts for a few hours to a few days

Apart from occasional febrile convulsions, Apart from occasional febrile convulsions, complications are most unusual and immunity complications are most unusual and immunity to infection appears lifelong.to infection appears lifelong.

Roseola InfantumRoseola Infantum

Non specific maculopapular rash with a central distribution developed as fever, subsiding on the third of illness.

Erythema infectiosumErythema infectiosum (Fifth disease) (Fifth disease)

Etiological agent- Parvovirus type B19 was Etiological agent- Parvovirus type B19 was only made in 1984. This is a small DNA virus.only made in 1984. This is a small DNA virus.

Causes a biphasic illness in susceptible Causes a biphasic illness in susceptible volunteers.volunteers.

About one week after infection there is a About one week after infection there is a viraemia for a few days. At this time there are viraemia for a few days. At this time there are non-specific symptoms but 7-10 days later non-specific symptoms but 7-10 days later there is rash and arthralgia. there is rash and arthralgia.

Erythema InfectiosumErythema Infectiosum

Fifth disease is seen usually in school-age Fifth disease is seen usually in school-age children.children.

The incubation period is 4-14 days and The incubation period is 4-14 days and infection is probably spread by droplets.infection is probably spread by droplets.

A short prodrome of fever may occur in adults A short prodrome of fever may occur in adults but is rare in children in whom the rash is but is rare in children in whom the rash is often the only feature.often the only feature.


The rash has three stages The rash has three stages First is the `slapped cheeks' appearance. First is the `slapped cheeks' appearance. Second- A variable, often reticular rash on the limbs. Second- A variable, often reticular rash on the limbs. Third stage, this peripheral rash may appear to settle, Third stage, this peripheral rash may appear to settle,

only to reappear with temperature, exercise or only to reappear with temperature, exercise or emotion. emotion.

Some patients have systemic features with fever, Some patients have systemic features with fever, adenopathy and gastrointestinal symptoms.adenopathy and gastrointestinal symptoms.


The rash on face is frequently described as having a “slapped checks appearance.”


The rash on the extremities often clears centrally to produce a lace-like appearnce.

Erythema infectiosumErythema infectiosum

Parvovirus-specific IgM can be detected and Parvovirus-specific IgM can be detected and used as a diagnostic test.used as a diagnostic test.

After acute infections adults are likely to After acute infections adults are likely to remain fatigued and depressed for several remain fatigued and depressed for several weeks. weeks.

It is also recognised that parvovirus infection It is also recognised that parvovirus infection may affect the fetus and lead to spontaneous may affect the fetus and lead to spontaneous abortion or hydrops fetalis.abortion or hydrops fetalis.

Herpes SimplexHerpes Simplex

The herpes viruses are all large DNA viruses The herpes viruses are all large DNA viruses and herpes simplex virus (HSV) is typical. and herpes simplex virus (HSV) is typical.

Herpes simplexHerpes simplex

Electron micrograph of HSV from vesicle fluid.


The virus is unable to survive for long in the The virus is unable to survive for long in the environment and does not penetrate intact environment and does not penetrate intact keratinized skin. Transmission is principally keratinized skin. Transmission is principally by intimate contact. by intimate contact.


Following primary infection, the virus induces Following primary infection, the virus induces lifelong latent infection in sensory nerve lifelong latent infection in sensory nerve ganglia.ganglia.

Recurrent infection occurs frequently.Recurrent infection occurs frequently.


Primary HSV skin infections may occur at any Primary HSV skin infections may occur at any site as a result of direct inoculation of the virus site as a result of direct inoculation of the virus through traumatized skin.through traumatized skin.

This may occur as a result of wrestling This may occur as a result of wrestling (herpes gladiatorum) or other contact sports (herpes gladiatorum) or other contact sports such as rugby football.such as rugby football.

by transfer of infection from oral sites to other by transfer of infection from oral sites to other areas via the fingers areas via the fingers


Primary infection on the wrist of a young man.


Genital infection in an infant due to implantation of the virus carried on the hand from primary herpetic stomatitis.


Recurrent cutaneous HSV may also occur at Recurrent cutaneous HSV may also occur at any site and then may mimic herpes zoster .any site and then may mimic herpes zoster .

Although there may be some prodromal Although there may be some prodromal symptoms of tingling or itching, systemic symptoms of tingling or itching, systemic symptoms are not usually seen and the rash symptoms are not usually seen and the rash does not usually have a clear dermatomal does not usually have a clear dermatomal distributiondistribution


Recurrent infection in a zoster like distribution over the face.


Patients whose cellular immunity is compromised by Patients whose cellular immunity is compromised by disease or immunosuppression are at increased risk of disease or immunosuppression are at increased risk of severe HSV infections.severe HSV infections.

Thus, patients with hematological or lymphoreticular Thus, patients with hematological or lymphoreticular malignancies, those who have received organ or malignancies, those who have received organ or bone-marrow transplants and patients with AIDS are bone-marrow transplants and patients with AIDS are at particular risk of severe and persistent cutaneous at particular risk of severe and persistent cutaneous disease due to HSV.disease due to HSV.


Severe lesions with skin necrosis in a patient with leukemia.


The diagnosis of HSV infections of the skin The diagnosis of HSV infections of the skin can usually be made upon clinical grounds.can usually be made upon clinical grounds.

If there is any doubt, vesicle fluid can be If there is any doubt, vesicle fluid can be examined for virus particles by electron examined for virus particles by electron microscopy, or scrapings from the floor of microscopy, or scrapings from the floor of suspect lesions can be examined by the Tzanck suspect lesions can be examined by the Tzanck test.test.


T zanck test preparation showing multinucleate giant cell.

Varicella (Chicken Pox)Varicella (Chicken Pox)

Varicella-zoster virus (VZV) is Varicella-zoster virus (VZV) is morphologically indistinguishable from herpes morphologically indistinguishable from herpes simplex virus.simplex virus.

It is transmitted from person to person by the It is transmitted from person to person by the respiratory route and the virus may arise either respiratory route and the virus may arise either from the oropharynx of a patient late in the from the oropharynx of a patient late in the prodrome of the illness or from vesicular fluid prodrome of the illness or from vesicular fluid during the first 3-4 days of each skin lesion.during the first 3-4 days of each skin lesion.

Varicella Chicken PoxVaricella Chicken Pox

The incubation period of varicella is usually The incubation period of varicella is usually 14 or 15 days with a range of 11-20 days.14 or 15 days with a range of 11-20 days.

In children there is rarely any prodromal In children there is rarely any prodromal illness; fever and rash are the initial illness; fever and rash are the initial manifestations of infection.manifestations of infection.

Adults more commonly have myalgia, Adults more commonly have myalgia, arthralgia, fever and chills for 2-3 days before arthralgia, fever and chills for 2-3 days before the rash appears.the rash appears.


The eruption of chicken pox is discrete, The eruption of chicken pox is discrete, varying in severity from a few spots to a very varying in severity from a few spots to a very profuse rash. profuse rash.

Each lesion starts as a tiny macule which Each lesion starts as a tiny macule which rapidly becomes papular and then rapidly becomes papular and then vesiculopustular.vesiculopustular.

The rash often starts on the scalp. The rash often starts on the scalp.


Electron micrograph of enveloped virus particles from vesicle fluid.


The vesicles are very superficial and there is The vesicles are very superficial and there is little or no induration around the lesion.little or no induration around the lesion.

After a few hours to a few days, the lesion is After a few hours to a few days, the lesion is scratched or becomes inspissated: in either scratched or becomes inspissated: in either case the fluid is replaced by a central scab . case the fluid is replaced by a central scab .

varicellavaricella

Within a few days of early rash, most of the lesion have become scabs of varying size.

varicellavaricella

The distribution of chicken pox is central.The distribution of chicken pox is central. The rash is more dense on trunk and face and The rash is more dense on trunk and face and

becomes less so peripherally.becomes less so peripherally. Lesions are often found on the mucous Lesions are often found on the mucous

membranes of the conjunctivae or mouth and. membranes of the conjunctivae or mouth and.

varicellavaricella

General view of severe rash showing characteristic distribution of lesions, with lesions most numerous centrally.

varicellavaricella

Shallow ulcers on the hard palate.

varicellavaricella

Lesions commonly occur within the mouth.

varicellavaricella

Varicella skin lesions may be more numerous Varicella skin lesions may be more numerous on an area of skin that has been subject to on an area of skin that has been subject to sunburn, irritation or mechanical trauma.sunburn, irritation or mechanical trauma.

varicellavaricella

In this young boy the lesion are most confluent in the antecubital fossa and over the neck areas where he had previously suffered from atopic eczema

varicellavaricella

In the normal individual secondary infection In the normal individual secondary infection of the lesions with staphylococci or of the lesions with staphylococci or streptococci is the only frequent complication streptococci is the only frequent complication although haemorrhagic chickenpox with although haemorrhagic chickenpox with disseminated intravascular coagulation and disseminated intravascular coagulation and pneumonitis occasionally occurpneumonitis occasionally occur

varicellavaricella

Scratching of the lesions not in frequently leads to secondary infection with streptococci or staphylococci and hence cellulitis around individual lesions.

varicellavaricella

Purpura fulminans and disseminated intravascular coagulation complicating chicken fox in immunocompetent adult woman.

varicellavaricella

The clinical diagnosis of varicella is usually The clinical diagnosis of varicella is usually not difficult. not difficult.

if laboratory assistance is required then it can if laboratory assistance is required then it can be done by finding typical herpes virus be done by finding typical herpes virus particles in the vesicular fluid by electron particles in the vesicular fluid by electron microscopy.microscopy.

The appearances are identical to those of HSV The appearances are identical to those of HSV and only culture will distinguish between the and only culture will distinguish between the different herpes viruses. different herpes viruses.

Herpes ZosterHerpes Zoster(shingles)(shingles)

Following the initial infection with VZV, the Following the initial infection with VZV, the virus, as for other herpesviruses, persists in the virus, as for other herpesviruses, persists in the individual in a latent form.individual in a latent form.

VZV remains in the dorsal root ganglia but the VZV remains in the dorsal root ganglia but the exact nature of the latent state is unknown.exact nature of the latent state is unknown.

ShinglesShingles

Cellular immune system is chiefly responsible Cellular immune system is chiefly responsible for maintaining the virus in the latent state as for maintaining the virus in the latent state as anything that depresses this form of immunity anything that depresses this form of immunity is associated with a more frequent reactivation is associated with a more frequent reactivation of VZV. of VZV.

ShinglesShingles

When it is seen in a young child who has When it is seen in a young child who has never suffered from varicella , the virus will never suffered from varicella , the virus will have been transmitted in utero from the mother have been transmitted in utero from the mother who had chickenpox during pregnancy.who had chickenpox during pregnancy.

Following reactivation of virus there is Following reactivation of virus there is degeneration of the cells of the dorsal root degeneration of the cells of the dorsal root ganglion and the virus then affects the area of ganglion and the virus then affects the area of skin supplied by the sensory nerves from that skin supplied by the sensory nerves from that ganglion.ganglion.

ShinglesShingles

When it occurs in a child as young as this 8 month old it is often as a result of primary infection in utero.

ShinglesShingles

High power view of base of vesicle showing inclusion bodies.

ShinglesShingles

The resultant illness usually begins with pain in the The resultant illness usually begins with pain in the areas of distribution of the affected posterior nerve areas of distribution of the affected posterior nerve root(s), followed by the rash.root(s), followed by the rash.

The rash is unilateral and involves 1-3 adjacent The rash is unilateral and involves 1-3 adjacent dermatomes.dermatomes.

There is often a faint erythema before the typical There is often a faint erythema before the typical vesiculopustular eruption. vesiculopustular eruption.

Any dermatome(s) may be involved although the Any dermatome(s) may be involved although the thoracic dermatomes are affected in about half the thoracic dermatomes are affected in about half the cases.cases.

ShinglesShingles

A bond of faint erythema in the distribution of an intercoastal nerve, the first physical sign of shingles, can be seen. The patient had been in pain for several days.

ShinglesShingles

A typical mature rash showing regular vesicles of varying size with an erythematous base.

shinglesshingles

The single most commonly involved The single most commonly involved dermatome is that of the trigeminal nerve. dermatome is that of the trigeminal nerve.

The ophthalmic branch is most commonly The ophthalmic branch is most commonly affected but shingles in the distribution of the affected but shingles in the distribution of the maxillary or mandibular branch is occasionally maxillary or mandibular branch is occasionally seen.seen.

shinglesshingles

Rash involving maxillary division of the trigeminal nerve.

shinglesshingles

The most frequently affected dermatome is that of the opthalmic division of the trigeminal nerve.

shinglesshingles

Lesions in the distribution of the maxillary division of the trigeminal nerve.

shinglesshingles

Lesion in the distribution of the mandibular division of the trigeminal nerve.

ShinglesShingles

The complications of herpes zoster The complications of herpes zoster Ramsay-Hunt syndrome - a variety of other Ramsay-Hunt syndrome - a variety of other

neurological complication and ocular neurological complication and ocular problems after trigeminal involvement. problems after trigeminal involvement.

The most frequent problem is, however, post-The most frequent problem is, however, post-herpetic neuralgia which is more common in herpetic neuralgia which is more common in the elderlythe elderly

Molluscum ContagiosumMolluscum Contagiosum

Molluscum contagiosum is a benign disease Molluscum contagiosum is a benign disease caused by the poxvirus family and spread by caused by the poxvirus family and spread by close human contact. close human contact.

The lesions are characteristic firm white The lesions are characteristic firm white nodules which vary greatly in number and tend nodules which vary greatly in number and tend to persist for a period of a few weeks to a few to persist for a period of a few weeks to a few months. months.

Sometimes they may be found in clusters Sometimes they may be found in clusters along a scar. along a scar.


Electron micrograph of the virus, appears as a cylindrical shape with rounded ends and a criss-cross pattern of nucleoprotein strands.


Several fleshy lesions with ambilicated centers on the face. They tend to regress and disappears after some months.


The lesions may be single or multiple. The lesions may be single or multiple. Each begins as a reddish papule that becomes Each begins as a reddish papule that becomes

a large haemorrhagic pustule on a red base.a large haemorrhagic pustule on a red base. Lymphadenopathy may be present.Lymphadenopathy may be present. The lesions are usually, but not always , on the The lesions are usually, but not always , on the

hands.hands.

Molluscum contagiosumMolluscum contagiosum

Orf. Papular lesions on the hand. Patient also has severe erythema multiforme with arthritis. The proximal interphalangeal joints can be seen to be

swollen.


Orf. Large pustular lesion on the hand of a farm worker.


Orf. Early lesion on the face.


The pustule may become umbilicated and then The pustule may become umbilicated and then rupture to leave an ulcerated nodule with a rupture to leave an ulcerated nodule with a grey crust.grey crust.

Erythema multiforme may occur after a week Erythema multiforme may occur after a week or two.or two.


The diagnosis is usually made clinically but The diagnosis is usually made clinically but can be confirmed if necessary by electron can be confirmed if necessary by electron microscopy, which reveals the large, ovoid microscopy, which reveals the large, ovoid virus particles.virus particles.

WartWart

Papilloma viruses, which produce human Papilloma viruses, which produce human warts, are small DNA viruses . warts, are small DNA viruses .

There are more than 50 different types of There are more than 50 different types of human papilloma virus (HPV) .human papilloma virus (HPV) .

Common warts (verrucae vulgaris), plantar Common warts (verrucae vulgaris), plantar warts (verrucae plantaris), flat or planar warts warts (verrucae plantaris), flat or planar warts (verrucae plana) and condylomata acuminata (verrucae plana) and condylomata acuminata

WartsWarts

Electron micrograph showing papiloma virus.

WartsWarts

Most common warts are 2-10mm in diameter Most common warts are 2-10mm in diameter (although they may coalesce to larger masses), (although they may coalesce to larger masses), flesh-coloured or brown, keratotic papules flesh-coloured or brown, keratotic papules with a rough surface. with a rough surface.

wartswarts

On mucosal surfaces the warts may be On mucosal surfaces the warts may be filiform with a narrow base and finger-like filiform with a narrow base and finger-like projections.projections.

Flat warts ares smaller, flat topped, non-Flat warts ares smaller, flat topped, non-scaling, skin-coloured papules and seen scaling, skin-coloured papules and seen especially in groups upon the hands, neck or especially in groups upon the hands, neck or face. face.

wartswarts

Common warts. Hand and fingers are common site.

wartswarts

Treatment with cryosurgery or with topical Treatment with cryosurgery or with topical lactic and salicylic acid paint is used for lactic and salicylic acid paint is used for common or flat warts. common or flat warts.

wartswarts

End of Viral Skin DiseasesEnd of Viral Skin Diseases

viral skin infection

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