Dermatology

Question 1

What is the characteristic rash of scarlet fever? (4) Other symptoms/fx? (4)

Answer 1

• Fine scarlet, erythematous blanching rash
• init on trunk –> limbs
• “patchy sunburn appearance”
• “sandpaper texture” = pathognomonic
• circumoral sparing/pallor - 7-10d post desquamation
• preceeding GAS/GABHS infection (fever, sore throat, etc.)
• strawberry tongue

Question 2

What is the etiology of scarlet fever? (2)

Answer 2

GAS/GABHS — release pyrogenic exotoxin

Question 3

What is tx of scarlet fever?

Answer 3

Penicillin V PO BID

Question 4

What are complications of untreated scarlet fever? (5)

Answer 4

Pna, sepsis, myocarditis, ARF, PSGN, DEATH

Question 5

DDx for scarlet fever rash? (3)

Answer 5

Kawasaki Disease
TSS (lacks sandpaper texture, lacks perioral sparing, +hemodynamic instability)
Fifth disease (parvob19) – facial then truncal, well child, strawberry tongue/sandpaper less common

Question 6

What is the time course of HSP?

Answer 6

• URI may preceed onset of sx by 1-3 weeks
• joint pain often < 48h
• AP often < 72h
• rash resolution by 4-6 weeks

Question 7

How would you describe the HSP rash?

Answer 7

purpuric rash on the limbs (primarily lower) + buttocks (esp dependent surfaces), typically in children 2-8 years old with other typical symptoms

Question 8

What are complications of HSP?

Answer 8

Renal – hematuria/proteinuria –> nephrotic syndrome, ARF/CRF
GI – intussusception, bloody stool, spont perforation, pancreatitis
Subcut edema – esp scrotum, hands, feet, sacrum
Recurrence – 50% in first year
Rare CNS + pulmonary complications

Question 9

What is management / dispo of HSP?

Answer 9

If renal involvement, significant GI etc, severe pain, admit
If otherwise, well, home with analgesia +/- steroids (more reserved for significant disease though!), regular follow-up to check renal function

Question 10

What is the typical presentation of pitryiasis rosea?

Answer 10

Typically skin / pink / salmon-coloured papules or patches, 1-2 cm diameter, often with larger herald patch.
Often parallel to ribs “Christmas-tree” pattern.
May have mild scaling, may have pruritis

Question 11

What is the time course / treatment of pitryiasis rosea?

Answer 11

Supportive care; zinc-ox, calamine, antiH for pruritis.

Typically last 6 - 12 weeks

Question 12

What type of reaction is EM (erythema multiforme)? What are typical causes (5 classes)?

Answer 12

Hypersensitivity Rxn

1) Viral (HSV, influenza, hepatitis)
2) Fungal (dermatophytosis, histoplas, cocciodi)
3) Bacterial (Strep, AC)
4) Collagen / rheum disorders (RA, SLE, dermatomyositis, periarteritis nodosa)