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ichthyosis A genetic disorder of keratinization in
which the cells the SKINsheds as part of its contin-
ual renewal cluster on the skin’s surface in scale-
like formations. The lesions itch and flake, and the
involved surfaces of the skin become very dry,
reddened, and inflamed. Ichthyosis may affect
limited areas of the skin or most of the skin’s sur-
face, depending on which of several GENEmuta-
tions is responsible for the condition. Ichthyosis is
chronic and lifelong, with symptoms first appear-
ing in early childhood. Ichthyosis may be heredi-
tary or acquired. Symptoms of hereditary
ichthyosis are present at birth and can be severe,
often affecting the eyes and eyelids.
The dermatologist can usually diagnose
ichthyosis on the basis of its appearance, though
may biopsy several lesions to confirm the diagno-
sis. Treatment attempts to restore moisture to the
skin as well as to accelerate exfoliation (remove
dead cells from the skin’s surface). Lotions,
creams, and ointments containing lanolin or other
emollients help the skin retain moisture, which
eases the itching and INFLAMMATION. Topical prod-
ucts that contain fruit acids such as alphahydroxy
acid or lactic acid help remove dead cells.
Severe ichthyosis may require topical or oral
treatment with a retinoid medication such as
isotretinoin. The scaly lesions tend to overlap one
another and can trap BACTERIAand other microor-
ganisms normally present on the skin’s surface,
causing INFECTION that requires treatment with
topical or oral ANTIBIOTIC MEDICATIONS. An ophthal-
mologist should provide monitoring and care to
detect and promptly treat EYEsymptoms to pre-
vent permanent damage to the CORNEAand to pre-
serve vision.
See also DERMATITIS;KERATITIS; LESION; MUTATION;
PRURIGO; PSORIASIS.

impetigo A contagious bacterial INFECTIONof the

SKINthat most commonly affects young children.

Staphylococcal or streptococcal BACTERIA are the

usual culprits, typically taking advantage of

breeches in the skin’s integrity that result from

rashes, insect bites, and other minor wounds. The

infection begins as small blisters, often around the

MOUTH, that itch and burn. Scratching or touching

the blisters and then touching other parts of the

body spreads the infection. Contact also spreads

the infection to other people. After two or three

days the blisters rupture, ooze, and crust. The

crust is characteristically honeylike in color and

appearance. The blisters remain contagious as long

as they are present.

Treatment is a topical antibiotic applied to the

blistered areas. The doctor may also prescribe an

oral antibiotic medication when the infection

extends to multiple areas of the body. The blisters

begin to recede within 24 to 48 hours of initiating

treatment, which eases the itching and discomfort.

The blisters are no longer contagious at this stage,

and generally heal completely within five to seven

days. Frequent HAND WASHING with antibacterial

soap and warm water helps stop the spread of

impetigo among children, family members, and

caregivers. Prompt cleansing and treatment of

minor skin irritations reduces the opportunity for

impetigo to develop.

See also ANTIBIOTIC MEDICATIONS; BLISTER; RASH;

TINEA INFECTIONS.

ingrown hair A new HAIRthat curls as it grows,

slicing into the side of the hair follicle instead of

arising from it to extend above the surface of the

SKIN. An ingrown hair forms a painful red bump.

The hair may grow its way through the wall of the

follicle and above the skin, or may block the folli-

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