Quick Review: Viral Skin Diseases

00:01 Alright, time for a quick review.

00:03 As always, I'll ask some questions, you can hit the pause button while you come up with your own answer, and then unpause it and we'll go through the answer ourselves.

00:11 So first off, all of the following are true of molluscum contagiosum except: Alright, it is definitely caused by a poxvirus so that's not our answer.

00:28 Number 2 - lesions typically resolve within 7 to 14 days.

00:34 Well, as we've discussed, these lesions can last for months so that's definitely gonna be our answer because they don't resolve in 7 to 14 days.

00:41 Thirdly, it is most common in children and the immunocompromised, that's true.

00:45 Aside from the skin lesions, patients are typically asymptomatic and that stands in stark contrast to so many other viral exanthem kind of presentations where patients have constitutional symptoms, so that is true.

00:56 And lastly, it is in fact characterized by dome-shaped umbilicated papules.

01:01 Answer is number 2.

01:03 Okay, question 2.

01:05 Which of the following is true of this lesion? Alright, number 1 - it's most commonly caused by HPV serotypes 6 and 11.

01:21 Well, we know that that lesion is herpes labialis that is caused by HSV not HPV, so we can take that one off the list.

01:29 Number 2 - most often accompanied fevers, by lymphadenopathy and myalgias.

01:35 Well that may be true of an initial primary infection.

01:38 You're not gonna see it with herpes labialis which is a secondary infection.

01:42 Number 3 - the lesion is best treated with imiquimod? Nope, it's gonna be treated with antiviral medications especially if we catch it early.

01:50 Number 4 - this lesion represents a secondary recurrence of herpes simplex vuirus That is absolutely true.

01:57 This would be caused by HSV-1 reactivation.

02:00 And lastly, it represent an immune-mediated hypersensitivity reaction No, that would be characteristic of erythema multiforme but this is a direct viral infection right in the skin and we would culture it if we unearth a vesicle, we'd find HSV-1 there.

02:15 So the answer, number 4.

02:20 Okay, next question.

02:22 What are some differences between an acrochordon which again is a skin tag, and a genital wart known as condyloma accuminata? Alright, we've got 2 pictures here to help us out.

02:38 Rememebr that both these lesions, the skin tag on the left and the genital wart on the right are painless pedunculated papulous lesions.

02:47 However, skin tags are not sexually transmitted, in fact they don't involve viruses or infections whatsoever.

02:53 You're gonna find them on the neck creases, particularly in folks with acanthosis nigricans, maybe in the axillae or the groin.

02:59 In contrast, HPV is the virus that causes these sexually transmitted infections, genital warts on the right-hand side.

03:07 Okay, here's the next question: A child presents with fevers, myalgias, lymphadenopathy and these diffuse rash composed of vesicles on erythematous base scattered throughout his torso and extremities.

03:20 All of the following are true of this presentation, except: Number 1 - the rash is referred to as a viral exanthem.

03:35 That's definitely true.

03:37 Number 2 - later in life, the causative agent may reactivate causing painful vesicles in a dermatomal distribution.

03:45 Sounds like we're talking about VZV infection and shingles.

03:48 This is looking like varicella-zoster virus infection so I would say yes to that one.

03:54 Number 3 - unroofing a vesical and sending a PCR is unlikely to reveal the causative agent.

04:01 That's false.

04:02 If we unroof those vesicles, we will absolutely find VZV inside the vesicle.

04:08 So that's gonna turn out to be our answer.

04:10 Number 4 - childhood vaccination against this agent is standard of care, that's true.

04:14 Most developed nations make it mandatory to get chickenpox or varicella virus vaccination And number 5 - this acute presentation will spontaneously resolve without treatment within 5 to 10 days.

04:27 And that's also true No treatment is required other than supportive care.

04:30 So our answer, number 3.

04:33 Unroofing of vesicle would find this culprit agent.

04:39 Okay, last question: All of the following are appropriate treatments except: Okay, watchful waiting for molloscum contagiosum? Totally appropriate.

04:57 Oral valcyclovir for herpes labialis also a completely reasonable decision.

05:02 Number 3 - topical salicylic acid for common warts.

05:06 Yup, that's one of the recommended approaches.

05:09 Supportive care for erythema multiforme That's also what we do.

05:13 And lastly, oral acyclovir for plantar warts That's not gonna work.

05:18 Plantar warts really require something like topical imiquimod or cryotherapy.

05:23 Oral acyclovir would be for an HSV1 or HSV2 infection.

05:28 With that, I think we've covered a lot of ground today And we're done.