Viral Skin Infections
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Transcript Viral Skin Infections
Viral Skin Infections
Ziad Elnasser, MD, Ph.D
Skin rashes
World wide, Nonimmune, human reservoirs,
respiratory tract.
Mumps, Measles, Rubella .
Erythema infectiosum and Parvovirus B19.
Roseola Infantum (Exantheme Subitum) and
HHV6 and HHV7.
Poxviruses.
Herpes viruses.
Mumps
Mumps
Paramyxovirus one antigenic type.
NA, HA on envelope.
Parotitis, aseptic meningitis in children.
Acute orchitis in adults.
Communicable 7days before to 9 days
after.
Late winter to spring.
Local replication, viremia, salivary glands
and CNS, second viremia then organs.
Kidneys.
Cell necrosis and inflamation.
IgM, then IgG, CMI might contribute.
Permanent immunity.
IP=12 to 29 days ave. 16-18 days.
Unilateral or Bilateral.
Meningitis, encephalitis, transverse
myelitis, Pancreatitis, orchitis, Oophoritis.
Myocarditis, nephritis, arthritis, thyroiditis,
sensorineural deafness.
Saliva, CSF, Pharynx.
Primary monolayer of Monkey kidney cell
culture.
Cyncytial giant cells, viral agglutination.
Serology.
No specific therapy, only MMR one or two
doses.
Measles (Rubeola)
Paramyxovirus (Mobillivirus).
H, F proteins, CD46 receptor.
Fever, rash and immunesuppression.
More than 6 months of age.
Late winter and early spring.
95% infectivity, 3-5 days before to 4 days
after the disappearance of the rash.
Exanthemes and enanthemes
Pathogenesis
URT, intense infection, inclusion bodies in
the nucleus and the cytoplasm.
Viremia.
B and T cells, PMN’s, CMI and humoral
immunity effect, superinfection.
Warthin-Finkeldey cells.
Vasculitis and skin rash, exantheme and
enantheme (Koplik’s spots).
CNS involvement.
CMI suppression.
Humoral peaks in 2-3 weeks, persist at
low level.
Life long immunity.
5 day measles, IP=7-18 days, URT
symptoms, conjunctivitis, fever, Kopkik’s
spots, skin rash, LNs.
Mortality could reach 15-25%.
Bacterial superinfection in 5-15% (URT,
pneumonia, encephalitis,
thrombocytopenic purpora,
SSPE and evidence.
Clinical Diagnosis.
Viral isolation from oropharynx or urine.
Multinucleated giant cells.
Serology.
Treat complications.
MMR, once (12 to 15 months)or twice (4-6
years or 10-12 years), contraindications.
Rubella (German measles)
Mild benign childhood exantheme.
Profound effects on developing fetuses.
Togavirus, only in humans.
Agglutinates chicks RBC’s, Trypsin treated
O RBC’s.
Winter and spring, only 30-60% develop
clinical apparent disease.
Contagious 7 days before to 7 days after.
Infected babies spread the virus 6 M after
birth.
Rubella Virus
URT, LNs, Viremia up to 8 days before
rash to 2 days after.
CMI and Immune complexes, rash,
arthritis.
Maternal viremia, placenta, fetus and
congenital infection, vasculitis, impaired
oxygenation and chromosomal breakage.
Shedding prolonged, IgM and IgG for 4 Y.
Mononuclear cell infiltration, Ca++
deposition is delayed (Celery stalk).
Life long immunity.
Three day measles.
IP=14 – 21 days (16 average), fever, URT
symptoms, LNs.
Macular rash, faint, arthralgia, arthritis.
Risk for fetal damage is up to 80% in 2w, 6
– 10% by 14th, 20-30% over all.
Cardiac: PDA, Pulmonary valvular
stenosis.
Eye: Cataract, chorioretinitis, Glucoma,
Coloboma, cloudy cornea,
microophthalmia.
Sensorineural deafness, Liver, Spleen.
Thrombocytopenia, intrauterine growth.
CNS defects.
Late including DM, chronic thyroiditis,
Subacute panencephalitis (SPE).
Diagnosis: Clinically is not enough.
Respiratory secretions, Urine.
Cell culture.
PCR.
Serology, IgM significance.
MMR: RA 27/3 human diploid fibroblast
cell culture, female adults, hospital staff at
risk, contraindications.
Erythema infectiosum
Parvovirus B19.
SSDNA, cultured in BM cells, fetal liver
cells.
Blood group P as a receptor.
Anemia, and aplastic crises.
Indurated rash on the face (slappedcheek), LNs, spleen, liver.
Thrombocytopenia, nephritis, encephalitis.
PCR, and serology.
Parvovirus B19
Roseola Infantum (Exanthem Subitum).
Sudden rash.
HHV6, HHV7.
EBV, Adenovirus, coxsakieviruses and
echoviruses cause similar manifestations.
Faint macular rash.
Roseola infantum
Poxviruses
Birds, mammals, and insects.
DsDNA brick shaped, enveloped multiply
in the cytoplasm, 100x200x300 nm.
Variola, Vaccinia, Moluscum contagiosum,
orf, cowpox, and pseudocowpox.
Variola major (smallpox), V. minor
(alastrim).
Uniform papulovesicular rash, pustules
with significant mortality.
poxviruses
Survives well in the extracellular milieu.
Highly contagious, saliva, skin, articles
and fomites.
Eradicated in 1977. Only humans, no
carriers.
Concern for recurrence?
Cell lysis, eosinophilic inclusions
Guarnieri’s bodies.
IP=12-14 days, can be short to 4-5 days.
Fever, chills, myalgia, rash 3-4 days later.
Firm papulovesicles, pustular in 10-12 day
All in the same stage of evolution
Hemorrhagic rash (sledge hammer).
Diagnosis by taking vesicular scraping,
culture, electron microscopy, PCR.
Bacterial superinfection leads to death.
Edward Jenner, Vaccinia virus, combination,
Vaccination resembles real infection.
Vaccinia virus is used as a vector for vaccines
Molluscum contagiosum: Direct contact, IP=28w, pearl-like cheesy painless nodule,
curettage, eosinophilic inclusions (molluscum
bodies).
Orf, milkers nodules and cowpox.
Herpesviruses
Enveloped, DsDNA, painfull skin ulcers,
chickenpox, and encephalitis.
8 types:HSV1,2, CMV, VZV, EBV, HHV6,
HHV7, HHV8, alpha, beta and gamma.
Icosahedral capsid, large genome, cross
similarity.
Latency and reactivation.
Replication, IE, E, and L, role of TK,
polymerase, in antiviral effect.
Herpes simplex
dsDNA , linear, 50% similarity.
Recurrent ulcers in skin and mm, above
and below the waist, latency.
Humans only, 90% +ve abs for type1, type
2 sexual 15-30%. Cervix in 5-12%.
Acute infection, multinucleated giant cells,
latent infection of sensory and autonomic
nerve ganglion.
Latent infection, trigeminal, superior
cervical and vagal nerve ganglion, S2,S3
for HSV-2, antivirals doesn,t work.
Herpes simplex type 2
Asymptomatic or mild illness in secondary
infection.
Both Humoral and CMI are important,
ADCC mechanism.
Single vesicular legions, pustular, coalese
then ulcerate, ectoderm origin.
Cold sores, fever blisters, herpetic whitlow,
Corneal damage and blindness.
Encephalitis.
Primary and recurrent genital herpes
infection.
Neonatal herpes.
Tissue culture and CPE.
Tzanck test.
PCR.
Serology is of less value.
Acyclovir is used Foscarnet if R.
Valacyclovir, and Famciclovir.
Safe sex.
C-section.
Varicella-Zoster
Similar to HSV differ in the glycoproteins.
Human diploid cell culture.
Chickenpox and shingles.
90% get the disease before 10.
Spread via the respiratory tract, highly
contagious, winter and spring, 1-2 days
before the rash to 3-4 days into the rash.
URTI, LNs, viremia, RES, viremia, skin.
Chickenpox and zoster sensory Nerve root
ganglion. Dermatomes.
CMI and humoral are important. Reactivation
is more severe in Immunesuppressed.
Generalized vesicular rash, different stage of
evolution.
Progressive varicella and high mortality (20%)
CNS, pneumonia, hepatitis, nephritis.
Post herpetic neuralgia.
Fetal embryopathy in pregnant women,
microcephaly, cataract, chorioretinitis,
microphthalmia.
Diagnosis: clinical, IF, serological, PCR.
Treatment: Acyclovir, Famciclovir, valacyclovir
High titer Immunoglobulins within 96hrs.
Not effective in shingles, or if rash has
evolved.
Alive attenuated vaccine after 12 M, health
care workers.