Encyclopedia of Health and Medicine

134 The Integumentary System
Treatment may cause discomfort. Small lesions
typically heal in two to three weeks with minimal
or no scarring. Larger or numerous lesions may
result in pitting and scarring that will require subsequent
cosmetic treatment. Though removal ends
the threat of squamous cell skin cancer from existing
lesions, the likelihood is high that new lesions
will develop. Dermatologists recommend annual
or semiannual skin examinations for people who
have had actinic keratosis lesions removed.
Risk Factors and Preventive Measures
Actinic keratosis develops only in people who
have repeated or severe exposure to the sun or
other sources of ultraviolet radiation such as tanning
booths. It reflects longstanding damage, typically
that occurred in childhood or over decades of
sun exposure in adulthood. The lesions emerge
and progress over years and are most common in
people age 50 and older.
People who are likely to develop actinic keratosis
are those who:
• experienced severe SUNBURN as children (blistering
and peeling)
• are fair skinned and do not tan easily
• work outdoors
• engage in outdoor activities such as gardening
and sailing that result in prolonged sun exposure
• live in areas where sun intensity is high, such
as the southern United States
Preventive measures include avoiding outdoor
activities during the highest intensity of sunlight
(typically 10 a.m. to 3 p.m. daily) whenever possible,
and diligent SUN PROTECTION when outdoors
during daylight hours. Dermatologists recommend
wearing a full-brimmed hat and long sleeves
when extended sun exposure is unavoidable and
applying sunscreen to the face, backs of the hands,
and other skin surfaces that remain exposed. Sunscreen
should have a sun protection factor (SPF)
rating of 15 or higher and protect against both
ultraviolet A (UVA) and ultraviolet B (UVB).
See also LENTIGINES; SKIN SELF-EXAMINATION.
age spots
See LENTIGINES.
aging, integumentary changes that occur with
Though the premise of aging tends to conjure
images of WRINKLES and gray HAIR or baldness, the
SKIN, hair, and NAILS undergo numerous changes
across the lifespan.
Integumentary Changes in Youth
During infancy and early childhood, the integumentary
structures are soft and the hair may be
fine. By about age 10 or 11 years, the hormonal
shifts of PUBERTY are under way. Isolated pimples
may break out on the face, chest, and back. Hair
patterns begin to change as the sex hormones
stimulate SECONDARY SEXUAL CHARACTERISTICS such
as axillary (underarm) and pubic hair growth.
Within a few years the hair on the legs thickens
and darkens, and boys begin to sprout facial hair.
The sebaceous structures kick up sebum production,
and the dermis accelerates cell production to
accommodate new skin to cover what can amount
to several inches of new height each year. ACNE,
an inflammatory process involving the sebaceous
structures, is the most common skin condition
that occurs between the ages of 14 and 22.
The skin, hair, and nails outwardly remain relatively
stable during young adulthood, the third
and fourth decades of life, though are collecting
the cumulative effects of factors such as sun exposure,
scarring, and other evidence of life experience.
People who work outdoors or participate in
outdoor activities begin to show these effects earlier
than their counterparts who limit their exposure
the natural elements. Repeated sun exposure
may result in tanning, a look that may be fashionably
desirable though also causes LENTIGINES (freckles
and “age” spots), roughness, and wrinkles. The
hands may develop calluses and the feet CORNS.
Integumentary Changes in Midlife
At about age 40 the connective tissues throughout
the body begin to gradually lose elasticity, allowing
the skin to sag and form more wrinkles.
Dermatologists call this loss elastosis. As well, the
epidermis (outer layer of the skin) and the adipose
tissue (fat) beneath the skin both thin. The epidermis
becomes more fragile and susceptible to punctures
and tears. Though losing a little fat under the
skin might sound like a benefit when other areas of
the body are demonstrating an age-related propen-