Atopic dermatitis                                                                       

•  also referred to as atopic eczema; eczema = "boiling over"
•  intensely pruritic inflammatory skin disorder associated with "atopy": asthma,
   hayfever, and allergic conjunctivitis
•  strong familial aggregation

•  "The rash that itches, or the itch that rashes?"
 

Pathogenesis

•  basic defect in atopic dermatitis is unknown, but there are several characteristic
   physiologic and immunologic derangements in "atopic" individuals:
               - cutaneous inflammation mediated by T_h2 cells
                       (type 2 helper T cells producing Il-4 and IL-5)
               - elevated serum levels of IgE
               - impaired cutaneous barrier function
                       (increased transepidermal water loss leads to dry skin)
               - skin colonization and infection by Staphylococcus aureus
                             (the toxins of which may serve as superantigens to promote cutaneous inflammation)
               - the role of dietary factors in atopic dermatitis is probably overemphasized

Clinical

•  unlike psoriasis the appearance or basic morphology of atopic dermatitis is more
  difficult to describe
•  pruritus is usually the most outstanding clinical feature
• depending on the acuity of the skin disease there can be:
               - ill-defined erythema
               - tiny coalescing edematous papules or papulovesicles  
               - excoriations
               - crusting (if secondarily infected)
               - xerosis (or dry, scaly skin)

     
               
• depending on the acuity of the skin disease there can be:
               - lichenification

     
             
3 phases of atopic dermatitis:

- infantile (2 months to 2 years):
               - facial and extensor distribution

     

     

- childhood
               - greater tendency to xerosis
               - flexural distribution
               - more lichenification and excoriations

     

- adult
               - atopic dermatitis generally improves gradually with age, and may remit by
                 late childhood or early adulthood
               - lesser tendency to flexural localization
               - in adults, atopic dermatitis may primarily affect the hands

Treatment

• Avoid irritating factors
• Aggressive restoration of the cutaneous permeability barrier with bland emollients and
  moisturizers
• Topical glucocorticoids (creams or ointments)
• Topical or systemic anti-staphylococcal antibiotics
• Oral antihistamines