Atopic dermatitis, commonly called eczema, is ruefully known as the “itch that rashes.” Patients with this skin condition suffer from itchy, inflamed skin. The itching, which can be intense and miserable, often develops first. Though scratching momentarily relieves the itch, it also causes the development of inflammation or rash. The ensuing “itch-scratch-rash” cycle only worsens the dryness, itchiness, and overall appearance of the skin.
Healthy skin acts as a barrier to keep unwanted substances (such as allergens, irritants, and toxins) out of the body and keep good things in the body (such as moisture). When this barrier is not working properly, substances penetrate the skin and trigger an immune response. Breakdown in the skin barrier also leads to moisture loss in the skin. The end result is dry, itchy, inflamed areas of skin. Recent studies point to a defect in the skin barrier protein called filaggrin as a factor in disease development in some patients.
Atopic dermatitis often begins in childhood, usually infancy, and is more common in individuals who have hay fever or asthma, or have family members who do. The condition falls into a category of disease called “atopic,” which also includes food allergy, hay fever, and asthma. These diseases may develop one after the other over a period of years; this is known as the “atopic march.” Recognizing this progression can be helpful and lead to earlier diagnosis and treatment.