| 释义 |
contact dermatitis
contact dermatitisn. An acute or chronic skin inflammation resulting from contact with an irritating substance or allergen.contact dermatitisInflammation of the skin due to irritants or allergic reaction. Irritants can be chemicals, metals, certain plants, or drugs. Symptoms can vary in severity from itching to cracks and bleeding.Thesaurus| Noun | 1. | contact dermatitis - a delayed type of allergic reaction of the skin resulting from skin contact with a specific allergen (such as poison ivy)bubble gum dermatitis - an allergic contact dermatitis developed around the lips of children who chew bubble gumRhus dermatitis - contact dermatitis resulting from contact with plants of the genus Toxicodendrondermatitis - inflammation of the skin; skin becomes itchy and may develop blisters |
contact dermatitis
contact dermatitis[′kän‚takt dər·mə′tīd·əs] (medicine) An acute or chronic inflammation of the skin resulting from irritation by or sensitization to some substance coming in contact with the skin. contact dermatitis
Contact Dermatitis DefinitionContact dermatitis is the name for any skin inflammation that occurs when the skin's surface comes in contact with a substance originating outside the body. There are two kinds of contact dermatitis, irritant and allergic.DescriptionThousands of natural and man made substances can cause contact dermatitis, which is the most common skin condition requiring medical attention and the foremost source of work-related disease. Florists, domestic workers, hairdressers, food preparers, and employees in industry, construction, and health care are the people most at risk of contracting work-related contact dermatitis. Americans spend roughly $300 million a year in their quest for relief from contact dermatitis, not counting the considerable sums devoted by governments and businesses to regulating and policing the use of skin-threatening chemicals in the workplace. But exactly how many people suffer from contact dermatitis remains unclear; a 1997 article in the Journal of the American Medical Association notes that figures ranging from 1% to 15% have been put forward for Western industrial nations.Causes and symptomsIrritant contact dermatitis (ICD) is the more commonly reported of the two kinds of contact dermatitis, anf is seen in about 80% of cases. It can be caused by soaps, detergents, solvents, adhesives, fiberglass, and other substances that are able to directly injure the skin. Most attacks are slight and confined to the hands and forearms, but can affect any part of the body that comes in contact with an irritating substance. The symptoms can take many forms: redness, itching, crusting, swelling, blistering, oozing, dryness, scaliness, thickening of the skin, and a feeling of warmth at the site of contact. In extreme cases, severe blistering can occur and open sores can form. Jobs that require frequent skin exposure to water, such as hairdressing and food preparation, can make the skin more susceptible to ICD.Allergic contact dermatitis (ACD) results when repeated exposure to an allergen (an allergy-causing substance) triggers an immune response that inflames the skin. Tens of thousands of drugs, pesticides, cosmetics, food additives, commercial chemicals, and other substances have been identified as potential allergens. Fewer than 30, however, are responsible the majority of ACD cases. Common culprits include poison ivy, poison oak, and poison sumac; fragrances and preservatives in cosmetics and personal care products; latex items such as gloves and condoms; and formaldehyde. Many people find that they are allergic to the nickel in inexpensive jewelry. ACD is usually confined to the area of skin that comes in contact with the allergen, typically the hands or face. Symptoms range from mild to severe and resemble those of ICD; a patch test may be needed to determine which kind of contact dermatitis a person is suffering from.DiagnosisDiagnosis begins with a physical examination and asking the patient questions about his or her health and daily activities. When contact dermatitis is suspected, the doctor attempts to learn as much as possible about the patient's hobbies, workplace duties, use of medications and cosmetics, etc.-anything that might shed light on the source of the disease. In some cases, an examination of the home or workplace is undertaken. If the dermatitis is mild, responds well to treatment, and does not recur, ordinarily the investigation is at an end. More difficult cases require patch testing to identify the allergen.Two methods of patch testing are currently used. The most widely used method, the Finn chamber method, employs a multiwell, aluminum patch. Each well is filled with a small amount of the allergen being tested and the patch is taped to normal skin on the patient's upper back. After 48 hours, the patch is removed and an initial reading is taken. A second reading is made a few days later. The second method of patch testing involves applying a small amount of the test substance to directly to normal skin and covering it with a dressing that keeps air out and keeps the test substance in (occlusive dressing). After 48 hours, the dressing is taken off to see if a reaction has occurred. Identifying the allergen may require repeated testing, can take weeks or months, and is not always successful. Moreover, patch testing works only with ACD, though it is considered an essential step in ruling out ICD.TreatmentThe best treatment for contact dermatitis is to identify the allergen or irritating substance and avoid further contact with it. If the culprit is, for instance, a cosmetic, avoidance is a simple matter, but in some situations, such as an allergy to an essential workplace chemical for which no substitute can be found, avoidance may be impossible or force the sufferer to find new work or make other drastic changes in his or her life. Barrier creams and protective clothing such as gloves, masks, and long-sleeved shirts are ways of coping with contact dermatitis when avoidance is impossible, though they are not always effective.For the symptoms themselves, treatments in mild cases include cool compresses and nonprescription lotions and ointments. When the symptoms are severe, corticosteroids applied to the skin or taken orally are used. Contact dermatitis that leads to a bacterial skin infection is treated with antibiotics.Alternative treatmentHerbal remedies have been used for centuries to treat skin disorders including contact dermatitis. An experienced herbalist can recommend the remedies that will be most effective for an individual's condition. Among the herbs often recommended are:- burdock (Arctium lappa) minimizes inflammation and boosts the immune system. It is taken internally as a tea or tincture (a concentrated herbal extract prepared with alcohol).
- calendula (Calendula officinalis) is a natural antiseptic and anti-inflammatory agent. It is applied topically in a lotion, ointment, or oil to the affected area.
- aloe (Aloe barbadensis) soothes skin irritations. The gel is applied topically to the affected area.
A homeopath treating a patient with contact dermatitis will do a thorough investigation of the individual's history and exposures before prescribing a remedy. One homeopathic remedy commonly prescribed to relieve the itching associated with contact dermatitis is Rhus toxicodendron taken internally three to four times daily.Poison ivy, poison oak, and poison sumac are common culprits in cases of allergic contact dermatitis. Following exposure to these plants, rash development may be prevented by washing the area with soap and water within 15 minutes of exposure. The leaves of jewelweed (Impatiens spp.), which often grows near poison ivy, may neutralize the poison-ivy allergen if rubbed on the skin right after contact. Several topical remedies may help relieve the itching associated with allergic contact dermatitis, including the juice of plantain leaves (Plantago major); a paste made of equal parts of green clay and goldenseal root (Hydrastis canadensis); a paste made of salt, water, clay, and peppermint (Mentha piperita) oil; and calamine lotion.Key termsAntibiotics — Substances used against microorganisms that cause infection.Corticosteroids — A group of anti-inflammatory substances often used to treat skin conditions.Immune response — The protective reaction by the immune system against foreign antigens (substances that the body perceives as potentially dangerous). The immune system combats disease by neutralizing or destroying antigens.PrognosisIf the offending substance is promptly identified and avoided, the chances of a quick and complete recovery are excellent. Otherwise, symptom management-not cure-is the best doctors can offer. For some people, contact dermatitis becomes a chronic and disabling condition that can have a profound effect on employability and quality of life.PreventionAvoidance of known or suspected allergens or irritating substances is the best prevention. If avoidance is difficult, barrier creams and protective clothing can be tried. Skin that comes in contact with an offending substance should be thoroughly washed as soon as possible.ResourcesPeriodicalsBeltrani, Vincent S., and Vincent P. Beltrani. "Contact Dermatitis." Annals of Allergy, Asthma, and Immunology 78 (February 1997): 160-75.con·tact der·ma·ti·tisa T lymphocyte-mediated dermatitis (type IV hypersensitivity) resulting from cutaneous contact with a specific allergen (allergic contact dermatitis) or irritant (nonallergic contact dermatitis). Synonym(s): contact hypersensitivity (1) contact dermatitisn. An acute or chronic skin inflammation resulting from contact with an irritating substance or allergen.contact dermatitis Dermatology A dermatitis evoked by a substance in regular direct contact with the skin Types Irritant CD–accounts for 80% of occupational dermatitides and damages skin by nonimmune mechanisms–eg detergents, solvents, adhesives, ointments, etc; allergic CD is due to an immune skin response, and is more common in a nonoccupational setting and caused by allergy to various substances–eg, jewelry, rubber, latex, poison ivy, neomycin, etc. See Allergic contract dermatitis, Irritant contact dermatitis, Latex allergy. con·tact der·ma·ti·tis (kon'takt dĕr'mă-tī'tis) Inflammatory rash marked by itching and redness resulting from cutaneous contact with a specific allergen (allergic contact dermatitis) or irritant (irritant contact dermatitis).  CONTACT DERMATITIS: Allergic reaction to topical anestheticcontact dermatitisDermatitis due to contact with allergens or an irritating substance. Allergic contact dermatitis is caused by a T-cell–mediated hypersensitivity reaction to natural or synthetic environmental allergens. These combine with skin proteins, altering the normal autoantigens so that new, foreign antigens are created. Nonallergic contact dermatitis, also known as irritative contact dermatitis, is usually caused by exposure to a detergent, soap, or other skin irritant. Synonym: allergic contact dermatitis dermatitis venenata (1) See: illustrationSymptomsSkin 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. TreatmentTepid baths, cool compresses, topical astringents (such as solutions of aluminum acetate), antihistamines, and corticosteroids all provide some relief. illustrationSee also: dermatitiscontact dermatitis Skin inflammation (ECZEMA) caused by an allergic reaction to a substance that has been in contact with the skin.con·tact der·ma·ti·tis (kon'takt dĕr'mă-tī'tis) Inflammatory rash marked by itching and redness resulting from cutaneous contact with a specific allergen or irritant. contact dermatitis
Related to contact dermatitis: Irritant contact dermatitisWords related to contact dermatitisnoun a delayed type of allergic reaction of the skin resulting from skin contact with a specific allergen (such as poison ivy)Related Words- bubble gum dermatitis
- Rhus dermatitis
- dermatitis
|