Dermatitis
Dermatitis: Excerpt from Professional Guide to Diseases (Eighth Edition)
Inflammation of the skin, dermatitis occurs in several forms: atopic (discussed here), seborrheic, nummular, contact, chronic, localized neurodermatitis, exfoliative, and stasis. (See Types of dermatitis, pages 1258 to 1261.) Atopic dermatitis (atopic or infantile eczema, neurodermatitis constitutionalis, or Besnier’s prurigo) is a chronic inflammatory response often associated with other atopic diseases, such as bronchial asthma and allergic rhinitis.
Causes and incidence
The cause of atopic dermatitis is unknown, but a genetic predisposition may be exacerbated by such factors as food allergies, infections, irritating chemicals, temperature and humidity, and emotions. Approximately 10% of childhood cases are due to allergy to certain foods, particularly eggs, peanuts, milk, fish, soy, and wheat. Atopic dermatitis tends to flare up in response to extremes in temperature and humidity. Other causes of flare-ups are sweating and psychological stress.
An important secondary cause of atopic dermatitis is irritation, which seems to change the epidermal structure, allowing immunoglobulin (Ig) E activity to increase. Consequently, chronic skin irritation usually continues even after exposure to the allergen has ended or after the irritation has been systemically controlled.
Atopic dermatitis is most common in infants, usually developing between ages 1 month and 1 year, commonly in those with strong family histories of atopic disease. At least half of those cases clear by age 36 months. These children often acquire other atopic disorders as they grow older. Typically, this form of dermatitis flares and subsides repeatedly before finally resolving during adolescence. However, it can persist into adulthood. In adults, it’s generally chronic or recurring.
Signs and symptoms
Atopic skin lesions generally begin as erythematous areas on excessively dry skin. In children, such lesions typically appear on the forehead, cheeks, and extensor surfaces of the arms and legs; in adults, at flexion points (antecubital fossa, popliteal area, and neck).
During flare-ups, pruritus and scratching cause edema, crusting, and scaling. Eventually, chronic atopic lesions lead to multiple areas of dry, scaly skin, with white dermatographia, blanching, and lichenification.
Common secondary conditions associated with atopic dermatitis include viral, fungal, or bacterial infections, and ocular disorders.
Because of intense pruritus, the upper eyelid is commonly hyperpigmented and swollen, and a double fold occurs under the lower lid (Morgan-Dennie folds, Morgan folds, Dennie pleats, or Mongolian lines). Atopic cataracts are unusual but may develop between ages 20 and 40.
Kaposi’s varicelliform eruption, a potentially fatal, generalized viral infection, may develop if the patient with atopic dermatitis comes in contact with a person who’s infected with herpes simplex.
Diagnosis
A family history of allergy and chronic inflammation suggests atopic dermatitis. Typical distribution of skin lesions rules out other inflammatory skin lesions, such as diaper rash (lesions are confined to the diapered area), seborrheic dermatitis (no pigmentation changes, or lichenification occurs in chronic lesions), and chronic contact dermatitis (lesions affect hands and forearms, sparing antecubital and popliteal areas). Serum IgE levels are usually elevated.
Treatment
Effective treatment for atopic lesions consists of eliminating allergens and avoiding irritants, extreme temperature and humidity changes, and other precipitating factors; local and systemic measures relieve itching and inflammation. Antihistamines relieve itching and induce more restful sleep. Topical application of a corticosteroid ointment, especially after bathing, often alleviates inflammation. Between steroid doses, application of a moisturizing cream can help retain moisture. Systemic corticosteroid therapy should be used only during extreme exacerbations. Topical tacrolimus and pimecrolimus (an immunosuppressant known as a topical immunomodulator) are new agents used in patients older than age 2 who are intolerant of or unresponsive to conventional therapy. Weak tar preparations and ultraviolet B light therapy are used to increase the thickness of the stratum corneum. Antibiotics are appropriate if a bacterial agent has been cultured.
Special considerations
❑ Warn the patient that drowsiness is possible with the use of antihistamines to relieve daytime itching. If nocturnal itching interferes with sleep, suggest methods for inducing natural sleep, such as drinking a glass of warm milk, to prevent overuse of sedatives.
❑ Complement medical treatment by helping the patient set up an individual schedule and plan for daily skin care. Instruct the patient to bathe in plain water, according to the severity of the lesions, and to bathe with a special nonfatty soap and tepid water (96° F [35.6° C]) but to avoid using any soap when lesions are acutely inflamed. Advise the patient to shampoo frequently and apply corticosteroid solution to the scalp afterward, to keep fingernails short to limit excoriation and secondary infections caused by scratching, and to lubricate his skin after a tub bath. Advise the patient to avoid using any perfume or makeup that causes burning or itching.
❑ To help clear lichenified skin, apply occlusive dressings (such as plastic film) intermittently. This treatment requires a physician’s order, experience in dermatologic treatment, and can’t be used in all treatment modalities.
❑ Inform the patient that irritants, such as detergents and wool, and emotional stress, exacerbate atopic dermatitis.
❑ Be careful not to show any anxiety or revulsion when touching the lesions during treatment. Help the patient accept his altered body image, and encourage him to verbalize his feelings. Remember, coping with disfigurement is extremely difficult, especially for children and adolescents. Arrange for counseling, if necessary, to help the patient deal with this distressing condition more effectively.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Medical Books Excerpts
- Dermatitis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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