• Atopic dermatitis (AD) is a multifactorial dermatologic condition involving chronic inflammation of the skin.
• Sometimes referred to as eczema, a general term to describe skin that is erythematous, scaling, vesicular, and crusting.
• May be the initial condition signaling the progression to further allergic disease, known as the atopic march
• Associated immunoglobulin E (IgE)-mediated diseases
  • Allergic rhinitis
  • Asthma
  • Food allergies

• Prevalence
  • >10% of infants and young children may be affected.
  • ~5% of adolescents are affected.
  • In 2007, 18 million Americans had a self-reported diagnosis, with more than one-third having the diagnosis confirmed by a physician.
• Age
  • Predominantly disease of infancy and childhood
  • Onset occurs in first year of life in the majority of affected individuals.
• Sex
  • Both sexes are affected equally.

• The exact cause is unknown, but genetic and environmental factors play a role.
• Involves:
  • Dysfunction of the epidermal barrier and
  • Dysfunction of the immune system
    • Abnormal IgE-mediated (type I) reaction
    • Abnormal cell-mediated (type IV) reaction

• The hygiene hypothesis states that decreased exposure to microbes stunts immunologic maturation of Th1 cells.
• Other cells implicated in the development of AD
  • Macrophages
  • IgE-bearing Langerhans cells
  • Eosinophils
  • Mast cells
  • Resulting inflammatory reactions lead to disruption of the epidermis.
• Potential antigenic triggers
  • Airborne allergens (dust mites, cat and dog dander, molds, pollen)
  • Foods (especially milk, eggs, peanuts)
  • Infectious agents
  • Contact allergens
• Psychological stress may exacerbate AD.

Acute dermatitis

• Associated with:
  • Severe pruritus
  • Redness
  • Vesicles
  • Exudation
  • May have subacute pattern of pruritus, redness, and scaling

Chronic lesions

• Marked by:
  • Excoriations
  • Lichenification (thickened skin and deeper or exaggerated skin lines)
  • Postinflammatory hypopigmentation or hyperpigmentation

Infantile AD

• Eruption of erythematous papules on facial cheeks and extensor surfaces of arms and legs
• Dry hair, scaly scalp (often)

Childhood AD

• Begins at approximately 3 years and lasts through puberty
• The areas most affected include:
  • Antecubital and popliteal folds
  • Neck
  • Flexor surfaces of wrists and ankles
  • More subacute and chronic dermatitis.

Adult AD

• Additional clinical signs include:
  • Diffuse involvement of the body
  • Xerosis
  • Lichenification
  • Central facial pallor

Other clinical manifestations

• Keratosis pilaris
  • Characteristic goose flesh appearance secondary to multiple, small, skin-colored or mildly erythematous keratotic papules located on upper arms, thighs, and facial cheeks
• Lichen spinulosus
  • Tiny hairlike spines top the small papules that occur in crops on various locations
• Pityriasis alba
• Dennie-Morgan folds
• Urticaria
• Hyperlinear palms
• Juvenile plantar dermatosis
  • Mainly affects the feet, rarely the hands
  • Produces shiny, fissured skin on the plantar surfaces
• Nummular eczema
• Cataracts

• Seborrheic dermatitis

• Seborrhea is associated with scaling, commonly on the scalp, forehead, and around the eyebrows.
• Can be accompanied by pruritus
• Contact dermatitis (allergic and irritant forms)
  • Diagnosis often requires positive exposure history to the potential offending agent.
  • Limited in distribution on the body to the area of contact
  • More likely to have acute onset and localized appearance
• Psoriasis
• Scabies
• Dermatophyte infection
• Systemic immunologic or metabolic disorders
  
  • Wiskott-Aldrich syndrome
  • Leiner disease
  • Histiocytosis X
  • Ataxia telangiectasia
  • Ahistidinemia
  • Agammaglobulinemia
  • Hartnup disease
  • Hurler syndrome
  • Eosinophilic gastroenteritis
  • Acrodermatitis enteropathica
  • Phenylketonuria

• Diagnosis is determined solely by history and clinical examination.
• Criteria for diagnosis (patient characteristics to look for)
  • Major criteria (all must be present)
    • Pruritus
    • Typical morphology and distribution
      • Facial and extensor involvement during infancy and early childhood
      • Flexural lichenification and linearity by adolescence
    • Chronic or recurring dermatitis
  • Minor criteria (≥ 2 must be present)
    • Personal or family history of atopy (eg, asthma, allergic rhinoconjunctivitis, atopic dermatitis)
    • Immediate skin test reactivity
    • White dermatographism or delayed blanch to cholinergic agents
    • Anterior subcapsular cataracts
  • Associated conditions (≥ 4 must be present)
    • Xerosis, ichthyosis, hyperlinear palms
    • Pityriasis alba
    • Keratosis pilaris
    • Facial pallor, infraorbital darkening (allergic shiner)
    • Dennie-Morgan fold
    • Elevated serum IgE level
    • Keratoconus
    • Nonspecific hand dermatitis
    • Recurring cutaneous infections
• Patients may have AD and not meet these criteria.

• No routine laboratory studies are needed for diagnosis.
• Specific tests to rule out other disorders, on a case-by-case basis
  • If infections are recurrent, consider an immunodeficiency work up.
• Bacterial cultures of encrusted or exudative skin lesions/nares to detect staphylococcal organisms are warranted when:
  • Secondary infection is suspected
  • Improvement is not noted with standard therapy
• Patch testing may be considered to pinpoint potential antigenic triggers, which may add a component of contact dermatitis.
• Skin biopsy may be necessary when the definitive diagnosis is in question.

• Treatment of uncomplicated cases
  • Treatment to relieve dryness, inflammation, and pruritus and eradicate secondary bacterial infections
  • Daily applications of emollients (cream or ointment), especially after brief warm baths
    • Ointments are better than emollients in more severe cases.
    • If discomfort (stinging sensation) occurs or if ointment feels too occlusive (eg, in humid weather), creams can be substituted.
  • Bathing should last no longer than 5 minutes.
    • Mild soaps or nondetergent cleansers are recommended.
    • Pat dry with a towel and apply emollient immediately to all skin.
    • Apply prescription topical medicines to affected areas.
  • Inflammation is best treated with corticosteroids.
    • Generally, ointments tend to work better than creams.
      • Ointments remain the choice for chronic dermatitis in which dryness and lichenification predominate.
    • Creams
      • Sometimes preferred for cosmetic appeal
      • Can be used for acute weeping, erythematous lesions

• Treatment of complicated cases
  • If flares continue despite compliance with medication and appropriate skin care, a secondary infection may be responsible that requires treatment.
  • Many patients have significant colonization with Staphylococcus aureus.
    • If S aureus superinfection occurs, hospitalization for aggressive care and intravenous antibiotics may be required.
    • Skin cultures may help identify appropriate antibiotic sensitivities.
    • Application of nasal mupirocin may be necessary to eradicate bacterial carriage.
  • May also require treatment for herpes simplex virus, human papillomavirus (HPV), and molluscum contagiosum

Steroids

• Low-potency topical agents, such as 1% hydrocortisone or desonide:
  • Can be used for mild disease, even on the diaper area and face
  • Twice-daily dosing should be limited to a 2-week course or less.
• Mid- to high-potency steroids, such as triamcinolone or fluocinonide:
  • Can be used in more severe cases on the trunk and extremities
• Strong, halogenated steroids:
  • Should not be applied to the face, axillae, or groin
  • Oral systemic steroid taper should rarely be prescribed.
• Most worrisome side effects
  • Dermal and epidermal atrophy
  • Suppression of the pituitary-adrenal axis
  • Applying topical steroids to the occluded groin area of a diapered child increases the risk of systemic side effects.

Nonsteroidal immunomodulators and other topical medications

• Topical tacrolimus and pimecrolimus
  • Approved for children ≥ 2 years of age
  • Most efficacious in mild to moderate disease
  • Alternatives to topical steroids
  • Can be applied to the face
  • Theoretical risk of cancer

• Other topical medications, coal tar and doxepin, are not routinely prescribed by pediatricians.

Pharmacologic therapy

• Antihistamines may help relieve pruritus, especially if dermatitis accompanies allergic rhinitis, urticaria, and sleep disturbance.
  • Nonsedating antihistamines, such as loratadine, can be used daily.
  • The sedating antihistamines, hydroxyzine and diphenhydramine, are most useful at bedtime.
• Efficacy of alternative medicine, such as herbal or probiotic supplementation, remains unknown.

Behavior modification

• Teach the child to rub rather than scratch.
• Have the child wear mittens or socks on his or her hands when in bed at night to reduce the itch-scratch cycle.
• Trim the fingernails frequently to avoid trauma and infection.

Diet

• Dietary management is controversial, and changes should be made judiciously.
• Peanuts, milk, and eggs are the most common food culprits.
• If food allergies are highly likely, as determined by a pediatric allergist, then strict avoidance of foods that serve as antigenic triggers should be encouraged; the most common are:
  
  • Cow milk
  • Hen eggs
  • Soy
  • Peanuts
  • Tree nuts (and seeds)
  • Wheat
  • Fish and shellfish

Secondary infections

• Topical or oral antibiotics
  • Cephalexin
  • Dicloxacilli
  • Amoxicillin-clavulanate
  • Azithromycin
  • Clindamycin
  • Mupirocin (topical)
• HPV treatments

• Vesicants
• Immunomodulators
• Cryotherapy
• Ablation with carbon dioxide laser

• Molluscum contagiosum treatments
  • Manual expression
  • Cryotherapy
  • Topical application of cantharidin or imiquimod

• Widespread herpes infection requires treatment with intravenous acyclovir.

Aggressive interventions for severe cases

• Prescribed at the discretion of the skin experts
  • Systemic immunomodulators
  • Ultraviolet light therapy

• Severe cases requiring systemic immunomodulation
• Extensive secondary bacterial infection requiring intravenous antibiotics
• Widespread herpes infection (eczema herpeticum, Kaposi varicelliform eruption)

• Recalcitrant cases should be referred to a dermatologist or allergist.
• Secondary HPV or molluscum contagiosum infections should be referred to a dermatologist for aggressive treatment.

• S aureus superinfection
  • Hospitalization for aggressive care and intravenous antibiotics may be required.
  • Skin cultures may help identify antibiotic sensitivities.
  • Application of nasal mupirocin may be necessary to eradicate bacterial carriage.
• Herpes infection, known as eczema herpeticum or Kaposi varicelliform eruption:
  • Requires treatment with intravenous acyclovir.
• HPV infection
• Molluscum contagiosum infection

• AD cannot be prevented, but meticulous adherence to proper skin care can control symptoms and secondary infection.
• Moisturization of the skin with daily applications of emollients, especially after bathing, is crucial to keep the skin hydrated.
• Prophylactic avoidance of food allergens, both for lactating mothers and infants via exclusive breastfeeding in the first 6 months of life, may be helpful in families with a strong family history of atopy.

• Guidelines of Care for Atopic Dermatitis (PDF) (guideline) American Academy of Dermatology

• Pediatric Dermatology: A Quick Reference Guide (book) American Academy of Pediatrics

• Greer FR, Sicherer SH, Burks AW, American Academy of Pediatrics, Committee on Nutrition and Section on Allergy and Immunology. Effects of early nutritional interventions on the development of atopic disease in infants and children: the role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas. Pediatrics. 2008;121(1):183-191.  [PMID:18166574]

• Eczema (Atopic Dermatitis) (brochure) American Academy of Pediatrics