photoallergic contact dermatitis

Etiology

Dermatitis has many causes, , including contact with skin irritants (such as the oil that causes poison ivy or oak); venous stasis, with edema and vesicle formation near the ankles; habitual scratching, as is found in neurodermatitis; dry skin, as in winter itch; and ultraviolet light, as in photosensitivity reactions.

Treatment

When a source of dermatitis is identifiable (such as in contact dermatitis due to a detergent or topical cosmetic), the best treatment is to avoid the irritating substance and to cleanse the affected area immediately with mild soap and water. Once skin inflammation is established, topical corticosteroid ointments or systemic steroids (during extreme exacerbations), topical immunomodulator agents (in patients above age 2), weak tar preparations and ultraviolet B light therapy (to increase the thickness of the stratum corneum) and antihistamines may be used, with antibiotics reserved for secondary infections. Dermatologists may prescribe occlusive dressings intermittently to help clear lichenified skin.

Patient care

The patient should avoid known skin irritants. Tepid baths, cool compresses, and astringents sometimes help relieve inflammation and itch. Moisturizing creams or lotions following bathing help to retain skin moisture, but perfumed products should be avoided. Drug therapy is administered and evaluated for desired effects and adverse reactions. The patient is taught to apply topical medications and is educated about their most common side effects. Scratching is discouraged and the fingernails kept short to limit excoriation. The patient should be made aware that drowsiness may occur with antihistamine use and that driving or operating mechanical equipment should be avoided until the extent of this effect is known. Health care professionals should be careful not to show any negative feelings when touching lesions during assessment or treatment but should follow standard precautions. Skin changes alter body image, and the patient will need assistance in accepting and coping with what he or she may view as disfigurement. Children and adolescents may require and benefit from counseling to help them deal with emotional components of their condition.

Treatment

The patient should avoid soaps and ointments. Bathing is kept to a minimum, but bath oils may help to prevent drying of the skin. Clothing should be soft textured and should not contain wool. Fingernails should be kept short to decrease damage from scratching. Antihistamines may help reduce itching at night. Heavy exercise should be avoided because it induces perspiration. A nonlipid softening lotion followed by a corticosteroid in a propylene glycol base may effectively treat acute exacerbations; when large areas of the body are involved, oral steroids may be needed. Because of the adverse effects associated with corticosteroids, topical immunosuppressants such as tacrolimus that decrease T cell activity have been developed. Antistaphylococcal antibiotics may be needed to control secondary infection, introduced when scratching causes microfissures in the skin.

Symptoms

Skin changes, which appear 4 to 48 hr after exposure, depending on the degree of sensitivity to the allergen, consist of erythema, local edema, and blisters. The blisters may weep in severe cases. Most patients complain of intense itching. Signs and symptoms of the disease usually last 10 to 14 days. Re-exposure to the cause will trigger a relapse.

Treatment

Tepid baths, cool compresses, topical astringents (such as solutions of aluminum acetate), antihistamines, and corticosteroids all provide some relief.

When the skin involvement is extensive, the patient may become depressed because of the cosmetic changes.

Treatment

Therapy is directed at treating the underlying cause.

Etiology

It is associated with allergy to gluten and is often found in patients with celiac disease (gluten-sensitive enteropathy).

Symptoms

The lesions develop suddenly and spread peripherally. The disease is variable and erratic, and an attack may be prolonged for weeks or months. Secondary infection may follow trauma to the inflamed areas.

Treatment

Oral dapsone provides substantial relief of symptoms in a few days. Sulfapyridine also may be used.

Those sensitive to poison ivy may also react to contact with other plants, such as the mango rind and cashew oil. These plants contain chemicals that cross-react with the sap present in poison ivy, poison oak, and poison sumac.

Symptoms

Some time elapses between skin contact with the poison and first appearance of symptoms, varying from a few hours to several days and depending on the sensitivity of the patient and the condition of the skin. Moderate itching or a burning sensation is soon followed by small blisters; later manifestations vary. Blisters usually rupture and are followed by oozing of serum and subsequent crusting.

Prevention

Some barrier creams have been used to prevent poison ivy dermatitis. They are sprayed on the skin prior to anticipated contact with the plant.

Treatment

In mild dermatitis, antihistamines and a lotion to relieve itching are usually sufficient. In severe dermatitis, cool, wet dressings or compresses, potassium permanganate baths, and topical corticosteroids are often effective. In some instances intramuscular or oral corticosteroid therapy is used. If plant leaves are burned and the smoke inhaled, or if plant leaves are ingested, the patient should be directed to an emergency care center. Demulcents, fluids, morphine, and a high-protein, low-fat diet may be prescribed.

Patient care

Prevention is important in those with known sensitivity and in those with no previous contact with or reaction to the plant. Instruction of the patient focuses on helping the patient to recognize the plant, to avoid contact with it, and to wear long-sleeved shirts and long pants in wooded areas. If contact occurs, the patient should wash with soap and water immediately to remove the toxic oil. Contaminated clothing and pets also should be promptly and thoroughly washed because contact with such items may cause poison dermatitis in other members of the household.

Symptoms

The scalp may be dry with abundant grayish branny scales, or oozing and crusted (eczema capitis). The rash may spread to the forehead and postauricular regions. The forehead shows scaly and infiltrated lesions with dark red bases and localized loss of hair. The eyebrows and eyelashes may have dry, dirty white scales. Inflamed skin and scales may be present on the nasolabial folds or the vermilion border of the lips. On the sternal region, the lesions are greasy to the touch. Eruptions may also appear in interscapular, axillary, and genitocrural regions. Cold winter weather may worsen the condition.

Treatment

When the condition is limited to the scalp, frequent shampooing and use of mild keratolytic agents are indicated. Selenium-containing shampoos are helpful. Generalized seborrheic dermatitis requires careful attention, including scrupulous skin hygiene, frequent washing and shampooing with selenium sulfide suspension to remove scales, keeping the skin as dry as possible, and using dusting powders. Fluorinated corticosteroids may be applied topically to hairless areas, and systemic cortisone preparations may be required. The differential diagnosis includes psoriasis; it should be ruled out and neurologic conditions recognized as possible predisposing factors.

Patient care

The health care provider explains to the patient that the condition has remissions and exacerbations and that hormone imbalances, nutritional status, infection, and emotional stress influence its course. The patient is taught to apply prescribed corticosteroids to the body and face. Fluorinated corticosteroids should be used with caution near the eyelids, on the face, and in the groin. To avoid developing a secondary Candida yeast infection in body creases or folds, the patient is advised to cleanse these areas carefully, to dry gently but thoroughly, and to ensure that the skin is well aerated. He or she is taught to treat seborrheic scalp conditions (dandruff) with proper and frequent shampooing, alternating two or three different types of shampoo to prevent the development of resistance to a particular product. External irritants and excessive heat and perspiration should be avoided. Rubbing and scratching the skin are discouraged because they prolong exacerbations and increase the risk for secondary infection and excoriation, esp. since scaly, pruritic lesions present in skin areas with high bacteria counts. Oral antibiotics (such as tetracycline) may be prescribed (as for acne vulgaris) in small doses over a prolonged period to reduce bacterial colonization. The patient is advised to take tetracycline at least 1 hr before or 2 hr after meals, since the drug is poorly absorbed with food. The patient also is taught about the adverse effects of the drug (photosensitivity, birth defects, nausea, vomiting, and candidal vaginitis) and their management. Adherence to the treatment regimen is stressed to achieve optimal results. Psychological support or counseling is provided as necessary to deal with related body image concerns.

Etiology

This condition may be due to one of several fungi, including Hormodendrum pedrosoi or Phialophora verrucosa.