derm infections

Question 1

How is cellulitis treated?

Answer 1

oral cephalosporins or penicillinase-resistent beta lactams for 10-14 days; IV abx for severe cases or bacteremia; linezolid or IV vancomycin for MRSA. diabetics should receive broad coverage becuase ofa n increased risk of multiorganism infection

Question 2

what is a carbuncle?

Answer 2

a collection of multiple infected hair follicles causing an abscess

Question 3

what parts of the skin are involved in hidradenitis suppurativa?

Answer 3

chronic follicular occlusion and apocrine gland (!!) inflammation that cuases recurrent abscess in the axilla, groin, and perineum

Question 4

What are complications of hidradenitis suppurativa?

Answer 4

lare eroding facial abscess can cause cavernous sinus thrombosis

Question 5

What pathogens most commonly cause necrotizing fasciitis? Common exam findings?

Answer 5

group A strep, or multipathogen infection of fascial planes

-warm swollen skin, loss of sensation in involved tissue, fever, crepitus, discoloration, bullae

Question 6

What are causes of gangrene? What are the types of gangrene?

Answer 6

tissue necrosis due to poor vascular supply or severe infection.
dry gangrene: gradual necrosis of skin from vascular insufficiency, so skin is hard and dry
wet gangrene: necrosis due to acute vascular obstruction or infection causing blistering and swelling of involved area

Question 7

When might you see subcutaneous air on Xray or CT?

Answer 7

wet gangrene, necrotizine fasciitis

Question 8

What features suggest S. aureus vs. group A step for impetigo?

Answer 8

staph: vesicles/blisters
strep: pusutles
both are pruritic and have yellow crusted lesions

Question 9

How should varicella be handled during pregnancy?

Answer 9

check varicella immunity in all pregnant women. varicella immune globulin should be given to all nonimmune pregnant women

Question 10

What are complications of varicella virus that are seen among the immunocompromised?

Answer 10

encephalopathy or retinitis

Question 11

How soon will the rash appear in chickenpox?

Answer 11

sx begin 2 wks after exposure; rash should develop within 3 days of HA, malaise, fever, myalgias

Question 12

What is the course of chickenpox/shingles?

Answer 12

lesions may develop for up to 1 wk and resolve a few days after appearing. infective until lesions crust over

Question 13

When is acyclovir given for varicella?

Answer 13

severe chickenpox, chickenpox or shingles in immunocompromised, trigeminal nerve shingles,

Question 14

What are the labs for molluscum contagiosum?

Answer 14

giemsa and wright stains show large inclusion bodies

Question 15

How is scabies treated?

Answer 15

permethrin cream or oral ivermectin. benadryl for itching. wash linens, clothes, etc in hot water

Question 16

How is tinea versicolor diagnoesed and treated?

Answer 16

• Dx: KOH shows short hyphae and spores (spaghetti and meatballs), wood lamp shows extent of disease
• tx: oral ketoconazole for 5 days or topical antifungal

Question 17

intertrigo: diagnosis and treatment

Answer 17

KOH prep shows pseudohyphae; give topical antifungal agent and topical corticosteroid