Microbiology of Common Skin Pathogens-Viral Flashcards Preview

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Flashcards in Microbiology of Common Skin Pathogens-Viral Deck (29):

What viruses can cause vesicular/bullous lesions?

- HSV 1 & 2
- Varicella-zoster
- Coxsackie; enterovirus


What is herpetic whitlow?

- vesicles and pustules of the finger caused by HSV and commonly seen in nurses, physicians, and dentists who treat pts with HSV, or a child who sucks his thumb.
- Tzanck smear= multinucleated giant cells.


How do you treat herpetic whitlow?

- acyclovir


What is herpetic gladiatorum?

- herpes on the skin other than the finger.
- seen in WRESTLERS or other contact sports.


What is Eczema herpeticum?

- HSV of skin in association with eczema.


What is Chicken pox?

- rash characterized by clear vesicles on an erythematous base caused by VARICELLA.
- begins as PUSTULES, then progresses to ULCERS and then CRUSTED LESIONS.
- incubation period= 14-21 days (contagious during the time, until pox crust over).
- symptoms include fever and headache.


What is Zoster?

- reaction of latent varicella causing SHINGLES along a single dermatome.


How is varicella introduced to the body?

- via the RESPIRATORY tract.
*replicates within regional lymph nodes early, and then in liver and spleen later.


What are some complications of Varicella?

- varicella pneumonia (adults)
- encephalitis
- increased risk for invasive group A strep causing necrotizing fasciitis.


What are the symptoms of Zoster (Shingles)?

- severe pain in the affected dermatome.
- vesicles on skin.
*lasts about 1 week.


What are the complications of Zoster?

- postherpetic neuralgia (persistent pain).
- disseminated infection (immunocompromised).


What is Molluscum contagiosum?

- pearly papules with central umbilication (central depression) due to DNA pox virus.
- occurs due to skin-skin contact or contaminated fomites.
- usually seen in children under 5.


How long does Molluscum contagiosum take to self-resolve?

- months to years.


What HPV type causes anogenital warts (condyloma acuminatum)?

- 6 & 11


What is a common wart (verruca vulgaris)?

- hyperkeratotic papule; rough, irregular surface, usually on hands and knees.
*caused by HPV


What are the other types of HPV warts?

- flat warts (verruca plana)= flat or slightly elevated flesh colored warts.
- deep palmoplantar wart (myrmecia)= deep, round lesion; rough, keratotic surface surrounded by calloused skin; usually soles of feet.


What do the black dots represent in warts?

- necrosis of blood vessels.
*must remove basal cells bc these are the replicating cells that contain the virus.


What is 6th disease?

- Roseola or Exanthema subitum, caused by human herpesvirus 6 (7)


What are some general characteristics of EXANTHEMS in children?

- respiratory pathogens, which cause systemic infection (measles, rubella, erythema infectiosum, exanthema subitum).
- localized infection that disseminates via lymphatics or blood.
- rash is the result of an immune response to the virus.


What are the associated symptoms for MEASLES (paramyxovirus)?

- CCC= Conjunctivitis, Coryza (head cold, fever, sneezing), and Cough. Also Photophobia.
- Koplik's spots= grayish white lesion in the mouth.


What is Subacute Sclerosing Panencephalitis (SSPE)?

- rare brain inflammation associated with MEASLES occurring years after infection.


How do cases of MEASLES occur in the U.S. if it was eliminated in 2002?

- importation occurrence in unvaccinated individuals.


What are the characteristics of Rubella (Togavirus)?

- RNA, icosahedra, enveloped.
- lymphadenopathy
- fever (more mild than measles).


What complications are associated with Rubella (Togavirus)?

- arthralgia or arthritis in adult women.
- thrombocytopenic purpura
- encephalitis
- neuritis
- orchitis
*all rare.


*** What is Exanthema subitum?

- rash (small, slightly raised pink lesions on the trunk, but spares the face) associated with herpes virus 6 (HHV-6 Roseola) that classically occurs following a 3-4 day history of high fever.
- infects CD4 cells


*** What is Erythema infectiosum (5th disease)?

- "SLAP CHEEK" lacy rash on face caused by immune response to Parvovirus B19.
- usually 5-14 year olds.
- seen most often in the winter and spring.
- transmitted via respiratory route.


What are some complications of parvovirus B19?

- aplastic crisis in patents with chronic RBC disorders (sickle cell anemia).


What is Hand Foot and Mouth disease?

- rash affecting the hands, feet, and mouth due to infection with Coxsackie A or Enterovirus


What are the general characteristics of Enteroviruses (Echo, Coxsackie A, Polio)?

- spread fecal-orally and through respiratory secretions.
- most common in summer and fall.
- more common in CHILDREN.
- often asymptomatic