Dermatology 1 Flashcards
Impetigo and ecthyma: etiology
- Usually S.aureus or group A Streptococcus, both common skin flora
- Minor breaks in the skin
- Secondary “impetiginization” of eczema, insect bites, burns, or other underlying dermatoses
Impetigo and ecthyma: prevalence
- Very common in the young
- Common in people kept in close quarters with poor hygiene
- Usual presentation in just a few days, accounts for 10% of visits to dermatology clinics
GAS impetigo: characteristics
- Usually found on the face
- “Honey crusted” erosions becoming confluent, or multiple small pustules eroding and coalescing to form larger ones
GAS impetigo: DDx
- Bullous impetigo
- HSV outbreak
- Dermatophytosis
- Trauma
GAS impetigo: Tx
- Mupirocin ointment (Bactroban) TID to affected areas and the anterior nares
- Pt & others close to Pt should wash w/ antibacterial bar soap (e.g. Dial) daily
Bullous impetigo: Characteristics
- Multiple confluent bullae containing clear or slightly turbid fluid, easily broken
- When unroofed, a moist and shallow erosion is present
- Bullae are usually 1-3cm in diameter,
- Can occur anywhere but the palms and soles are spared
Bullous impetigo: DDx
- HSV, varicella, zoster
- Allergic conditions
- Thermal injuries
Bullous impetigo: Tx
- Carefully unroof and apply mupirocin ointment (Bactroban) TID to affected areas
- 5 day course
Ecthyma: Characteristic
- A large unroofed bulla that started as bullous impetigo, unroofed
- Forms an ulceration with a thickened, crusty or moist base that is occasionally necrotic
- Takes wks to form, often encountered on the legs
Ecthyma: DDx
- Vascular insufficiency
- Factitious disorders
- Diphtheria (very rare in the US)
Ecthyma: Tx
- Tx is usually systemic
Preferred- Decloxacillin or Cephalexin; if MRSA suspected/confirmed- Clindamycin, TMP-sulphamethoxasol (Bactrim), or Doxycyclin
Abscess: Characteristics
- A well-circumscribed collation of pus appearing as an acute or chronic localized infection and associated with tissue destruction
Abscess: Etiology
- Is most often caused by Staphylococcus spp
- Usually the result of some kind of wound infection or trauma
- Occurs gradually over days, sometimes weeks
Abscess: Sx
There is usually throbbing pain and the area is exquisitely tender
Abscess: Tx
- The treatment involves incision and drainage
Note: There is a fair amount of evidence to suggest that systemic treatment is not necessary unless constitutional symptoms are present
Furuncle: Characteristics
An acute, deep-seated, red, hot, tender nodule that may or may not have an abscess
Furuncle: Etiology
Is always associated with a hair follicle, is sometimes an “ingrown hair” related to depilatory treatments gone wrong
Furuncle: DDx
Hidratenitis suppurativa (comedolike follicular occlusion, chronic relapsing inflammation, mucopurulent discharge, and progressive scarring)
Furuncle: Tx
Is handled the same as with an abscess if pus is present, if the nodule has no lake of pus present, hot compresses can be applied and systemic antibiotics can be given
Furuncle: Prevention
Instruct Pts to trim instead of shave or change a razor blade frequently
Carbuncle: Characteristics
- A deeper infection comprised of interconnecting small abscesses usually arising in several contiguous hair follicles
- Arise slowly, over weeks