Dermatologic Emergencies and their Mimics (Sugarman, 9/30/2020)

 Thanks to Dr. Jeff Sugarman for an excellent Grand Rounds this week on Dermatologic Emergencies and their Mimics. Dr. Sugarman's presentations are always replete with photos ("A picture is worth a thousand words" for sure) and probing questions, so this post will be filled with the same. Answers can be found at the very end of the post in the COMMENTS section. Don't cheat; take the quiz and use the HINTS not only to guide you to your answers, but also to enhance your understanding of the condition. 

First, when should you worry about possible dermatologic emergencies?

• Age (newborn and young infants)
• High fever, toxicity
• Morphology: particularly blistering, mucosal involvement, hemorrhage
• Specific medications: anticonvulsants, antibiotics, NSAIDs

Remember the presentation was on dermatologic emergencies and their mimics. This summary/quiz contains both derm emergencies and benign derm conditions that look pretty similar, so keep serious and not serious things on your differential. 

1) What is this rash?

Hint #1: it's really common (especially in children and people with atopy)

Hint #2: morphology includes wheals, annular, dusky centers

Hint #3: time course is VERY helpful: lesions tend to self resolve in hours, disappear and reappear in different locations

Hint #4: triggers include allergy, autoimmunity, drugs (9%), URI (40%), and idiopathic (50%)

Hint #4: Treatment: non-sedating antihistamine (fexofenadine, cetirizine) in day, sedating antihistamine at night (hydroxyzine, diphenhydramine). 

Hint #5: Prednisone is NOT rx of choice-- it works really well, and then the rash will come right back as soon as it's stopped.

2) What is this rash?

Hint #1: Looks a lot like the first rash but is different.

Hint#2: Rash morphology includes target lesions with 3 zones: dusky center, pale edematous ring, peripheral erythematous margin

Hint #3: lesions are discrete, they do NOT coalesce

Hint #4: usually pts have no systemic symptoms

3) What is this rash?

Hint#1: Presents as dusky urticaria PLUS edema, +/- fever, malaise and arthritis (7-21 days after exposure)

Hint #2: Lesions last longer than true urticaria

Hint #3: This is a type III hypersensitivity reaction (immune complexes)

Hint #4: Triggers include meds (cefaclor, PCN, anti-cancer, anti-depressants, anticonvulsants, htn meds, anti-inflammatory meds), biologic agents (rituximab, infliximab, efalizumab), infections (strep, HBC, HCV)

4) What is this rash?

Hint #1: This is a form of leukocytoclastic vasculitis in children age <2 years old

Hint #2: Presents as purpuric edematous plaques with target-like pattern, often described as "cockade or rosette"

Hint #3: This includes dramatic skin findings, but children paradoxically are not really toxic

Hint #4: Rash tends to spare the trunk

Hint #5: Lesions resolve spontaneously in 1-3 weeks

Hint #6: No labs or treatment needed.

5) What is this rash?

Hint#1: This rash may accompany pneumonia by this same organism

Hint #2: Tends to be mucosal predominant (94% oral, 82% ocular, 63% GU) and is mucosal alone in 34% of cases

Hint #3: Mean age is 12 years old

Hint#4: Most patients (81%) have no long term sequelae

Hint #5: I never heard of this before this lecture by Dr. Sugarman

6) What is this rash?

Hint#1: Severe life-threatening mucocutaneous disease involving systemic signs: fever, respiratory symptoms

Hint #2: It's a clinical syndrome, there is no definitive diagnostic test

Hint #3: Always involves at least 2 mucous membranes (mouth, eyes, urethra)

Hint #4: Causes in kids include meds (antibiotics, antiepileptics, chemotherapy), as well as HSV, mycoplasma and some undetermined causes

7) What is this rash?

Hint #1: begins as localized often occult infection (can be in the nasopharynx, perioral, conjunctiva, umbilicus, paronychia, urine, middle ear)

Hint #2: Progresses to generalized erythema and skin fragility

Hint #3: Empiric treatment is anti-staph antibiotics (cover for MRSA)

Hint #4: Peeling is NOT full thickness

8) What is this rash?

Hint #1: Most common cause of nonsexually related acute genital ulcers (NRAGU)

Hint #2: Ulcers are painful, well demarcated, shallow erosions on a clean fibrinous base

Hint #3: Self-limiting condition, usually resolving spontaneously within 2-6 weeks

9) What is this rash?

Hint #1: thick crusts, thick walled pustules are common

Hint #2: facial, periorbital involvement common 

Hint #3: fever and pain are common

Hint #4: You should culture this

Hint #5: Keflex and mid-potency steroid for body (TAC) and low potency steroid (2.5% hydrocortisone) are both indicated

Hint #6: Bleach baths (1/2 cup in full bath, 1/4 cup in 1/2 bath) may also be indicated

10) What is this rash?

Hint #1: People with eczema are particularly vulnerable to this condition due to their disruption of epidermal barrier

Hint #2: Fever, malaise, and lymphadenopathy may be present

Hint#3: This is PAINful

Hint #4: Morphology includes "monomorphous punched out erosions" (especially if you look at the periphery of this rash)

Hint #5: Lesions favor areas of active dermatitis, particularly head, neck and trunk

Hint #4: There is often a delay in diagnosis of this condition

Hint#5: Viral culture/PCR will give you the answer

Hint #6: Prompt high dose acyclovir is treatment of choice (PO for mild, IV for mod/severe)