Removal or avoidance of the offending allergen is advised. The only effective measure for minimizing animal allergens from pets is removal of the pet from the home. Avoidance of pollen and outdoor molds can be accomplished by staying indoors in a controlled environment. Air conditioning and keeping windows and doors closed lower exposure to pollen. High-efficiency particle air filters reduce exposure to allergens (e.g., pet dander). Sealing the mattress, pillow, and covers in allergen-proof encasings is the most effective strategy for reduction of mite allergen. Bedding should be washed in hot water (>130 °F) every week.
Atopic dermatitis is a chronic, pruritic, relapsing inflammatory skin condition. The pathogenesis is multifactorial and involves a complex interplay of factors, including genetic predisposition, immunologic abnormalities, disturbances in skin barrier function, environmental interactions, and infectious triggers. Several genes encoding epidermal (filaggrin) or other epithelial structural proteins and genes encoding major elements of the immune system play a major role in atopic dermatitis.
Several immunoregulatory abnormalities have been described in patients with atopic dermatitis. There is an exaggerated cutaneous inflammatory response to environmentaltriggers, including irritants and allergens. Activated Langerhanscells in the dermis expressing surface-bound IgE stimulate Tcells. In acute lesions, activated Th2 lymphocytes infiltrate the dermis. They initiate and maintain local tissue inflammationprimarily through interleukin-4 (IL-4) and IL-13, which promote IgE production, and IL-5, which promotes eosinophil differentiation. As the disease progresses from an acute to a chronicphase, there is a switch from Th2 to Th1/Th0 cellular response.Chronic lesions are characterized by increased IL-12 and IL-18.
Patients with atopic dermatitis have hyperirritable skin,and many factors can cause the disease to worsen or relapse. Known triggers include anxiety and stress, climate (extremes of temperature and humidity), irritants, allergens, and infections. Approximately 35% to 40% of infants and young children with moderate to severe atopic dermatitis have coexisting food allergies. The more severe the atopic dermatitis and the younger the patient, the more likely a food allergy will be identified as a contributing factor. Egg allergy is the most common cause of food-induced eczematous reactions.
The prevalence of atopic dermatitis increased twofold to threefold over the past 30 years. Approximately 15% to 20% of children and 2% to 10% of adults are affected. Atopic dermatitis oftenstarts in early infancy. Approximately 50% of affected childrenshow symptoms in the first year of life, and 80% of these childrenexperience disease onset before 5 years of age. Atopic dermatitisis often the first manifestation of other atopic diseases. Approximately 80% of children with atopic dermatitis develop otherallergic diseases, such as asthma or allergic rhinitis. Symptomsof dermatitis often disappear at the onset of respiratory allergy.