Microbiology of Common Skin Pathogens-Viral

Question 1

What viruses can cause vesicular/bullous lesions?

Answer 1

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

Question 2

What is herpetic whitlow?

Answer 2

• 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.

Question 3

How do you treat herpetic whitlow?

Answer 3

• acyclovir

Question 4

What is herpetic gladiatorum?

Answer 4

• herpes on the skin other than the finger.

- seen in WRESTLERS or other contact sports.

Question 5

What is Eczema herpeticum?

Answer 5

• HSV of skin in association with eczema.

Question 6

What is Chicken pox?

Answer 6

• 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.

Question 7

What is Zoster?

Answer 7

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

Question 8

How is varicella introduced to the body?

Answer 8

• via the RESPIRATORY tract.

* replicates within regional lymph nodes early, and then in liver and spleen later.

Question 9

What are some complications of Varicella?

Answer 9

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

Question 10

What are the symptoms of Zoster (Shingles)?

Answer 10

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

Question 11

What are the complications of Zoster?

Answer 11

• postherpetic neuralgia (persistent pain).

- disseminated infection (immunocompromised).

Question 12

What is Molluscum contagiosum?

Answer 12

• 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.

Question 13

How long does Molluscum contagiosum take to self-resolve?

Answer 13

• months to years.

Question 14

What HPV type causes anogenital warts (condyloma acuminatum)?

Answer 14

• 6 & 11

Question 15

What is a common wart (verruca vulgaris)?

Answer 15

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

Question 16

What are the other types of HPV warts?

Answer 16

• 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.

Question 17

What do the black dots represent in warts?

Answer 17

• necrosis of blood vessels.

* must remove basal cells bc these are the replicating cells that contain the virus.

Question 18

What is 6th disease?

Answer 18

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

Question 19

What are some general characteristics of EXANTHEMS in children?

Answer 19

• 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.

Question 20

What are the associated symptoms for MEASLES (paramyxovirus)?

Answer 20

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

Question 21

What is Subacute Sclerosing Panencephalitis (SSPE)?

Answer 21

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

Question 22

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

Answer 22

• importation occurrence in unvaccinated individuals.

Question 23

What are the characteristics of Rubella (Togavirus)?

Answer 23

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

Question 24

What complications are associated with Rubella (Togavirus)?

Answer 24

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

Question 25

*** What is Exanthema subitum?

Answer 25

• 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

Question 26

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

Answer 26

• “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.

Question 27

What are some complications of parvovirus B19?

Answer 27

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

Question 28

What is Hand Foot and Mouth disease?

Answer 28

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

Question 29

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

Answer 29

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