Skin Infections
Skin is a natural barrier to infection. However, it frequently succumbs to attack by bacteria, viruses, parasites, and insects.
Skin infections are more common in people with:
- young or elderly age
- at-risk environment
- lowered immune system
- concurrent diseases or conditions
- medications (antibiotics, corticosteroids)
Infection History and Physical
history:
- time and course
- preveious skin disease and trauma
- contact with infected individuals
- recently used medications
- other symptoms (fever, malaise, etc)
physical exam:
- anatomical location and distribution
- follicular or non-follicular
- concurrent cutaneous or systemic disease
- constitututional symptoms
- lymphadenopathy, lymphangiitis, or edema
Bacterial Skin Infections
- Staphylococcus aureus
- most likely to cause disease
- local infections: folliculitis, furuncles, carbuncle, impetigo, ecthyma, cellulitis
- toxin related: scalded skin syndrome
- secondary infections
- Streptococcus
- local infections: impetigo, cellulitis, erysiplas, NF
- toxin related: scarlet fever, toxic shock syndrome
common viral skin infections
scabies
fungal infections (tinea)
affinity for keratin of skin, hair, and nails
named for site of involvement - tinea capitis, pedis, cruris, manum, facei, corporis, barbae, unguim (aka onychomycosis)
various species
yeast infections include Candidiasis and tinea versicolor
often scaling, with occasional pustules
tinea capitis can be varied in what it looks like
- alopecia (hair loss) is a good clue its a fungus
- have a high index of suspicion
management of fungal infections
- establish correct diagnosis
- KOH exam (easy to do where you are)
- Wood's light (a single wavelength) that lights up porphyrin
- negative doesn't exclude fungi
- fungal culture (takes a couple of weeks)
treatment of fungal infections
- topical antifungals (limited infections)
- clotrimazole, econazole, ketaconazole, terbenafine, ciclopirox)
onychomycosis
lamisil is taken systemically for 3 mothns, with ~80% experiencing cure
hand, foot, and mouth disease
warts
molluscum contagiosum