Atopic dermatitis (aka eczema): By David Robles, MD, PhD

Atopic dermatitis is the medical term for eczema. It is a fairly common skin condition, especially in children. It is characterized by an itchy rash usually on the flexural surface of the arms and backs of the knees in children and on the extensor surfaces of the extremities in adults. It relates to an impaired skin barrier, immune dysregulation and environmental interactions with the skin. 

Asthma, allergic rhinitis (also called Hayfever), and atopic dermatitis, constitute what we call the “atopic triad.” These three things often occur together. Many of my patients with eczema also have hay fever and/or asthma, or have a family member with one or more of the conditions in the triad. Think of it has having 'trigger sensitive immune cells'... in the sinuses that would result in Hayfever, in the skin that would cause eczema, and in the airways that would cause asthma.

Atopy is is associated with heightened immune responses to inhaled allergens and food allergens. Below are several physical findings in patients with atopy. Individuals with atopic dermatitis often have increased numbers and depth of skin lines (hyperlinearity) of the palms. A Dennie–Morgan fold/crease is a line in the skin below the lower eyelid caused by edema in atopic dermatitis and allergies. "Allergic Shiners" are dark circles under the eyes due to swelling and discoloration from congestion of small blood vessels in the eyelids. Allergic shiners are associated with allergies. 

Patients with Atopy may be more sensitive to dust mite, which may trigger asthma. Atopic dermatitis is worsened by skin contact with physical and chemical irritants. Factors that may worsen eczema include, emotional stress, food allergens, dust, soaps and detergents, and various cosmetic ingredients. Patients with atopic dermatitis should use fragrance-free products that are specifically formulated for sensitive skin. People with eczema may experience allergies to certain chemicals, perfumes, or metals, like nickel, more so than the average person. If your Dermatologist suspects that you may have a contact allergy (i.e., an allergy to something you are coming in contact with) then they may perform patch testing to find out what the culprit is. 

Eczema is associated with an increased risk of skin infection by Staphylococcus aureus. This is partly because of the itching and scratching but perhaps more importantly related to a decreased production of anti-microbial peptides in eczema skin. Researchers found that patients with eczema have a reduced production of natural anti-microbial peptides. Impetigo is caused by staphylococcus (staph) or streptococcus (strep) bacteria.

The skin normally has many types of bacteria on it and when there is a compromise in the skin barrier, bacteria can enter and cause inflammation and infection. In this case below, the child frequently licked her lips, which caused skin irritation and skin barrier dysfunction and allowed staph bacteria to take hold. Impetigo is most common in children and can spread to others. 

Treatment: Topical corticosteroid ointments are the mainstay of treatment but various other oral treatments exist and it is often responsive to ultraviolet light treatment, under the care of a dermatologist. When a staph infection is present your doctor will also prescribe antibiotics. 

Bleach baths taken once a week can reduce bacterial colonization and may be prescribed by your doctor. To prepare a bleach bath, fill a bath tub and add 1/4 to 1/2 cup of common liquid bleach (for example, Clorox) into the bath water. Soak in the bath for about 10 minutes and then rinse. 

People with eczema often have dry skin. If the skin gets extremely dry, usually on the lower extremities,  the skin may exhibit a criss-cross pattern of superficial cracks and fissures, known as eczema craquel√©. The skin looks like a “dried riverbed”. Hydrating ointments like pure petrolatum should be used at least twice daily and topical corticosteroid ointments prescribed by a dermatologist can be very effective. 

Follow David Robles, MD, PhD