Master the board step 3

Dermatology
Impetigo
This is a superficial bacterial infection of the skin limited largely to the
epidermis and not spreading below the dermal-epidermal junction. The infection
is described as “weeping,” “oozing,” “honey-colored,” or “draining.”
It occurs more often in warm, humid conditions, particularly when there is
poverty and crowding of children. It is both contagious and autoinoculable.
Impetigo can cause glomerulonephritis, but it will not cause rheumatic fever.
Impetigo is more often caused by Staphylococcus but is sometimes caused by
Streptococcus pyogenes, also known as group A Streptococcus.
Impetigo is treated as follows:
··
Apply topical antibiotics, such as mupirocin.
··
If topical antibiotics are not effective, then antistaphylococcal oral antibiotics
should be used.
Erysipelas
Erysipelas involves both the dermis and epidermis and is most commonly
caused by group A Streptococcus (pyogenes). Erysipelas is more likely than
other bacterial infections to result in the following:
··
Fever, chills, and bacteremia
··
Bright red, angry, swollen appearance to the face
Treatment is as follows:
··
Use the systemic oral or intravenous antibiotics previously described.
··
If there is culture confirmation of the organism as Streptococcus, then penicillin
G or ampicillin can be used.
Cellulitis
This is a bacterial infection of the dermis and subcutaneous tissues with Staph
and Strep.
Cellulitis is treated with the antibiotics previously described, based on the
severity of the disease. If there is fever, hypotension, or signs of sepsis or if
oral therapy has not been effective, then the patient should receive intravenous
therapy. Oxacillin, nafcillin, or cefazolin is the best therapy. Treatment
is generally empiric, because injecting and aspirating sterile saline for a specific
microbiological diagnosis has only a 20 percent sensitivity.
Folliculitis, Furuncles, and Carbuncles
These 3 disorders represent 3 different degrees of severity of staphylococcal
infection occurring around a hair follicle. Occasionally, folliculitis can occur
from Pseudomonas in those who contract it in a whirlpool or hot tub. As folliculitis
worsens from a simple infection superficially around the hair follicle,
297