Atopic dermatitis/eczema

Atopic dermatitis/eczema

Chris Schach

Author Bio -

Eczema">Atopic dermatitis/Eczema

(Atopic=allergy associated)  (derm=skin, titis=inflammation)

Key points

*is a common, chronic, pruritic (itching), inflammatory disease of the skin that flares and regresses

*is a rash marked by dry skin, red, scaly plaques often with lichenification (thickening of skin due to scratching) and excoriations(scratches)

*generally begins in the first year of life, regresses by around10 years of age, and resolves completely, in most patients, by adulthood

*is often associated with allergic rhinitis and/or asthma

Atopic dermatitis (AD), or Eczema, is an inflammatory disease of unknown origin that usually begins within the first few months of life. It is characterized by red scaly plaques, oozing, crusting, dry skin (xerosis), pruritic (itchy), and lichenification (thickening of the skin). AD is chronic and will relapse & remit over the course of the disease. AD, asthma, and allergic rhinitis are the parts of the inflammatory hypersensitivity triad.  There is a strong familial component to the development of this disease and 75% of patients with AD have a family history of atopy. AD affects between 10-20% of pediatric population making it the most common inflammatory skin disease in children. Only 1-3% of adults have AD demonstrating that most patients will out grow AD. Although the exact cause of AD has not been identified, the most current theory suggests that an inherited epidermal barrier dysfunction predisposes someone to develop AD.  Factors which may lead to flare-ups include heat, humidity, certain detergents/soaps, abrasive materials, exposure to chemicals or smoke, and stress. Secondary infections can sometimes result from excessive scratching, which produces breaks in the skin.

Presentation is slightly different depending on what age the patient is when they begin to have symptoms.

Infancy:  The rash generally appears suddenly on the face and head, especially the cheeks. The rash will be patchy if it is present elsewhere on the body and the diaper area is usually spared. The pruritus may be so strong as to cause the infants to rub their affected surfaces against furniture or carpeting, and may even cause them to have trouble sleeping. 

Childhood: Rash will usually appear in the creases of the knees and elbows. It may also appear around the neck, ankles, wrist, and crease of the buttocks. As children age with AD, they may develop thickened, leathery skin due to scratching.

Adulthood: Most children will grow out of AD.  The symptoms of scaly skin, dry skin, and pruritus are usually worse in adults. Rash usually appears first around the neck and in the creases of the knees and elbows. It may generalize to the rest of the body. In adults, AD is especially noticeable on the face and may be unbearably itchy around the eyes. Adults with a history of atopy are at increased risk for hand and foot dermatitis.

Differential Diagnosis

Diagnosis

Key points

*Diagnosis is usually based on history, especially family history, and physical examination of the skin.

*Although not usually necessary, IgE Levels > 1000ng/ml and increased blood eosinophils also support the diagnosis of AD.  Usually food allergies are not the cause of atopic dermatitis but may sometimes cause exacerbations.  Ocasionally, prick or patch tests maybe administered in an attempt to identify allergies. Testing may also need to be done to rule out immunodeficiencies.

Atopic Dermatitis is generally diagnosed based on appearance, then further classified by severity. Mild: few, scattered affected areas, which are treated with self-care measures
Moderate: extensive affected areas, more difficult to control with self-care measures and may require prescription medications. 
Severe:diffuse affected areas that are difficult to treat even with prescription medications

Health care professionals may also look into the affected person's family history for instances of atopic dermatitis in relatives, or instances of allergies such as hay fever and asthma, to assist in establishing a firm diagnosis. In cases where diagnosis is difficult, skin biopsies of the affected area may be taken for pathologic evaluation.

Treament

Key points

*Prevention is the most important aspect of treatment as there is no cure.

*Identify and avoid triggers.

*Maintain healthy skin

A key component to prevention is keeping the skin moisturized. This is accomplished by maintaining a moisturizing regiment, including the use of non-soap cleansers or moisturizing soaps, the application of thick moisturizers such as petroleum jelly after bathing. It is also important to protect your skin by minimizing exposure to elements which may exacerbate the condition, such as heat, humidity, soaps/detergents, abrasive materials, smoke/chemicals, seasonal changes, and stress.

In moderate to severe cases, health care professionals have several options for prescription treatments. Topical steroids can be used to treat affected areas, and oral antihistamines may be prescribed to reduce itching. If these treatments are unsuccessful immunomodulators such as Tacrolimus and pimecrolimus have shown considerable success in reducing symptoms.

If infection is present, topical or oral antibiotics may be used. If there is chronic skin breakage due to scratching occurs, dilute bleach baths may be recommended to stave off bacterial infection(1/4 -1/2 cup household bleach to full bath once or twice a week or as needed.  Warning:  higher concentrations of bleach may cause Burns or worsen skin irritation)

 References:

1. Rook’s Textbook of Dermatology

2. Clinical Dermatology 

3.General Dermatology

4. www.emedicinemedscape.com

5. www.up-to-date.com

6. www.dermnetnz.org

7. www.ncbi.nlm.nih.gov

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