++
Atopic dermatitis is a chronic disorder characterized by xerosis,
pruritus, scaly erythematous patches, and thickening of the skin
with enhancement of normal skin markings (lichenification). It is
frequently associated with a personal or family history of hay fever,
asthma, or allergic rhinitis. It can be divided into three phases
based on the age of the individual: infantile, childhood, and adolescent.
++
Although many patients and families will insist on “finding
the cause,” experience and studies confirm that specific
allergen identification and avoidance or dietary modification is
less helpful than focusing on skin treatment.
++
Age Onset usually from age 2 to
12 months, and almost all cases by age 5 years. Nearly 80% of
cases will resolve by adulthood.
++
++
Incidence Common and thought to
be increasing.
++
Hereditary Predisposition More
than two-thirds have personal or family history of allergic rhinitis,
hay fever, or asthma. Many children with atopic dermatitis develop
asthma and/or hay fever later in life.
++
Prevalence 10% to 15% of
the childhood population with significant regional variability.
++
The cause of atopic dermatitis is unknown; however, multiple
factors are known to play a role in the development of atopic dermatitis.
Certain genetic factors (such as filaggrin gene abnormalities) may
lead to xerosis while others may result in immune dysregulation.
Factors such as stress, climate, infections, irritants, and allergens
seem to play a role in many patients as well. For the vast majority
of patients, there is no one “trigger” or “cause,” but
rather an unfortunate collection of constituents that all can worsen
the disease.
++
Atopic dermatitis is sometimes called “the itch that
rashes.” Dry skin and pruritus are found in essentially
all patients. Scratching the skin leads to the characteristic eczematous
changes and a vicious itch-scratch cycle. Itching may be aggravated
by cold weather, frequent bathing (particularly with hot water),
wool, detergent, soap, and stress. The disease can wax and wane
unpredictably, however, which probably contributes to the numerous
misattributions of causes and remedies.
++
Type Patches and plaques with scale,
crust, and lichenification. Lesions usually confluent and ill defined.
++
++
Special Clinical
Features
++
Atopic children may demonstrate increased palmar markings, periorbital
atopic pleats (Dennie-Morgan lines), keratosis pilaris, or white
dermatographism. They also can develop widespread herpetic, wart,
molluscum, or tinea infections because of their impaired skin barrier
function.
++
Differential
Diagnosis
++
Atopic dermatitis can be confused with seborrheic dermatitis,
contact dermatitis, psoriasis, or scabies. Some metabolic disorders
may manifest eczematous dermatitis and should be considered, including
acrodermatitis enteropathica and phenylketonuria. Some disorders
of immunity may also include atopic dermatitis, ...