Facts on File Encyclopedia of Health and Medicine

as the doctor directs. In people who frequently
have folliculitis or who are on long-term antibiotic
therapy such as for ACNE, the INFECTIONmay resist
the common first-line antibiotics, requiring fur-
ther therapy with a different antibiotic. Folliculitis
usually heals without scarring or residual compli-
cations.

HOT TUB FOLLICULITIS

The hot, moist environment of a hot tub is the

ideal incubator for various BACTERIA, notably the

Pseudomonas aeruginosa. The warm water of the

hot tub opens the pores, giving the bacteria

access to the HAIRfollicles. When the pores close

after leaving the hot tub, they trap P. aeruginosa,

which thrives in the moist setting. Folliculitis

results, often appearing on the SKINthe same pat-

tern of the clothing worn in the tub.

See also CARBUNCLE; FURUNCLE; PSEUDOFOLLICULITIS
BARBAE.

freckles See LENTIGINES.

frostbite Damage to the SKINthat results from

prolonged exposure to extremely cold tempera-

tures. Frostbite occurs when the fluid in cells crys-

tallizes into ice, causing the skin and often the

underlying tissues to freeze. The fingers, hands,

toes, feet, NOSE, and ears are most vulnerable to

frostbite. People who have impaired peripheral

circulation are at increased risk. Frostbite also can

damage blood vessels, interrupting the blood sup-

ply. When this occurs, GANGRENE(tissue death) and

subsequent loss of the body part are significant

threats.

Symptoms and Diagnostic Path

Any loss of feeling following extended exposure to

the cold raises suspicion of frostbite and is the first

factor to consider when evaluating potential frost-

bite. The ice crystals that form cause the skin to

become hard, pallid, and cold to the touch. There

is loss of feeling and function, and the skin may

BLISTER. Skin that has remained frostbitten for a

long time may already be gangrenous or necrotic

(blackened and dead). As it warms, frostbitten

frostbite 159

FROSTBITE SEVERITY

Degree of Damage Characteristics Recovery Implications

first degree spots of whitened, hardenedSKINinvolving primarily the recovery with no residual complications
epidermis
erythema (redness) of adjacent skin; localized
edema (swelling)
distorted or absent sense of touch or clumsy movements

second degree areas of whitened, hardened skin involving the epidermis recovery with some residual
and dermis complications (scarring)
erythema of adjacent skin; regional edema
loss of feeling and movement
fluid-filled blisters

third degree white, hard skin with frostbite extending through the layers recovery with moderate residual
of the skin and into the subcutaneous tissue complications (tissue loss and scarring)
regional edema
loss of feeling and movement
blood-filled blisters
fourth degree white, hard skin with frostbite extending through the skin significant loss of tissue, with AMPUTATION
and into supporting tissues and structures likely
GANGRENEor necrosis; regional edema