Dermatitis is a nonspecific term that means inflammation of the skin. There are many causes and patterns of skin inflammation, including eczema, contact dermatitis, and atopic dermatitis. Eczema is the most common type of skin inflammation and can occur in three stages: acute, subacute, and chronic.
Eczema is frequently seen on the hands or feet, but can occur or any part of the body. Acute eczema may be vesicular and red, whereas subacute eczema lacks the vesicles and has more prominent scaling and cracking of the dry skin. In chronic eczema there is lichenification (thickened plaque with accentuation of the skin lines). Nummular eczema is coin shaped (from the Latin nummis, coin). Contact dermatitis is an allergic response to an allergen such as the chemical found in the poison ivy or poison oak plant (rhus dermatitis). These lesions are often linear and vesicular. Other contact allergens include nickel in jewelry and belt buckles, and chemicals in deodorants.
Atopic dermatitis is a type of eczematous eruption that is itchy, recurrent, and symmetrical and often found on flexural surfaces. These patients often have either a personal or family history of asthma, allergic rhinitis or conjunctivitis. In infancy, atopic dermatitis often presents on the face. After infancy, the dry, scaling and red lesions are found in flexural areas such as the antecubital or popliteal fossa. Most atopic dermatitis is not due to specific allergens, but is set off by a number of trigger factors in patients with a strong genetic predisposition to develop eczematous eruptions.
General Treatment of Dermatitis
Direct patients to avoid skin irritants
Use emollients to moisten skin
Apply topical steroids
Use oral antihistamines for itching
Prescribe oral antibiotics for superinfection (weeping/crusting)
The treatment modalities for all types of dermatitis have basic principles in common. Major trigger factors to avoid are drying soaps and bathing in water that is too hot or for too long. Many soaps and hot water dry out the skin which increases the pruritus and inflammation. Emollients or moisturizers are used to moisten the skin. The inflammatory component is treated with an appropriate topical steroid. Strength and vehicle should be determined by the lesions, chronicity, and location.
Because itching is a prominent feature of many types of dermatitis, efforts should be made to stop the scratch-the-cycle. This is especially true for atopic dermatitis and lichen simplex chronicus. Lichen simplex chronicus often needs the most potent topical steroid ointments to penetrate the thick plaque and moisturize the cracked pruritic skin. The oral sedating antihistamines work well to stop itching (especially at night).
Any type of dermatitis may develop a bacterial superinfection by the most common skin organisms. This may take the form of impetigo or just show weeping and crusting. Signs of infection should be treated with an antibiotic that covers GABHS and S. aureus.