Dermatitis (redirected from allergic dermatitis)

Dermatitis 

Definition

Dermatitis is a general term used to describe inflammation of the skin.

Description

Most types of dermatitis are characterized by an itchy pink or red rash.

Contact dermatitis is an allergic reaction to something that irritates the skin and is manifested by one or more lines of red, swollen, blistered skin that may itch or seep. It usually appears within 48 hours after touching or brushing against a substance to which the skin is sensitive. The condition is more common in adults than in children.

Contact dermatitis can occur on any part of the body, but it usually affects the hands, feet, and groin. Contact dermatitis usually does not spread from one person to another, nor does it spread beyond the area exposed to the irritant unless affected skin comes into contact with another part of the body. However, in the case of some irritants, such as poison ivy, contact dermatitis can be passed to another person or to another part of the body.

Stasis dermatitis is characterized by scaly, greasy looking skin on the lower legs and around the ankles. Stasis dermatitis is most apt to affect the inner side of the calf.

Nummular dermatitis, which is also called nummular eczematous dermatitis or nummular eczema, generally affects the hands, arms, legs, and buttocks of men and women older than 55 years of age. This stubborn inflamed rash forms circular, sometimes itchy, patches and is characterized by flares and periods of inactivity.

Atopic dermatitis is characterized by itching, scaling, swelling, and sometimes blistering. In early childhood it is called infantile eczema and is characterized by redness, oozing, and crusting. It is usually found on the face, inside the elbows, and behind the knees.

Seborrheic dermatitis may be dry or moist and is characterized by greasy scales and yellowish crusts on the scalp, eyelids, face, external surfaces of the ears, underarms, breasts, and groin. In infants it is called "cradle cap."

Causes and symptoms

Allergic reactions are genetically determined, and different substances cause contact dermatitis to develop in different people. A reaction to resin produced by poison ivy, poison oak, or poison sumac is the most common source of symptoms. It is, in fact, the most common allergy in this country, affecting one of every two people in the United States.

Flowers, herbs, and vegetables can also affect the skin of some people. Burns and sunburn increase the risk of dermatitis developing, and chemical irritants that can cause the condition include:

Contact dermatitis can develop when the first contact occurs or after years of use or exposure.

Stasis dermatitis, a consequence of poor circulation, occurs when leg veins can no longer return blood to the heart as efficiently as they once did. When that happens, fluid collects in the lower legs and causes them to swell. Stasis dermatitis can also result in a rash that can break down into sores known as stasis ulcers.

The cause of nummular dermatitis is not known, but it usually occurs in cold weather and is most common in people who have dry skin. Hot weather and stress can aggravate this condition, as can the following:

Atopic dermatitis can be caused by allergies, asthma, or stress, and there seems to be a genetic predisposition for atopic conditions. It is sometimes caused by an allergy to nickel in jewelry.

Seborrheic dermatitis (for which there may also be a genetic predisposition) is usually caused by overproduction of the oil glands. In adults it can be associated with diabetes mellitus or gold allergy. In infants and adults it may be caused by a biotin deficiency.

Diagnosis

The diagnosis of dermatitis is made on the basis of how the rash looks and its location. The doctor may scrape off a small piece of affected skin for microscopic examination or direct the patient to discontinue use of any potential irritant that has recently come into contact with the affected area. Two weeks after the rash disappears, the patient may resume use of the substances, one at a time, until the condition recurs. Eliminating the substance most recently added should eliminate the irritation.

If the origin of the irritation has still not been identified, a dermatologist may perform one or more patch tests. This involves dabbing a small amount of a suspected irritant onto skin on the patient's back. If no irritation develops within a few days, another patch test is performed. The process continues until the patient experiences an allergic reaction at the spot where the irritant was applied.

Treatment

Treating contact dermatitis begins with eliminating or avoiding the source of irritation. Prescription or over-the-counter corticosteroid creams can lessen inflammation and relieve irritation. Creams, lotions, or ointments not specifically formulated for dermatitis can intensify the irritation. Oral antihistamines are sometimes recommended to alleviate itching, and antibiotics are prescribed if the rash becomes infected. Medications taken by mouth to relieve symptoms of dermatitis can make skin red and scaly and cause hair loss.

Patients who have a history of dermatitis should remove their rings before washing their hands. They should use bath oils or glycerine-based soaps and bathe in lukewarm saltwater.

Patting rather than rubbing the skin after bathing and thoroughly massaging lubricating lotion or nonprescription cortisone creams into still-damp skin can soothe red, irritated nummular dermatitis. Highly concentrated cortisone preparations should not be applied to the face, armpits, groin, or rectal area. Periodic medical monitoring is necessary to detect side effects in patients who use such preparations on rashes covering large areas of the body.

Coal-tar salves can help relieve symptoms of nummular dermatitis that have not responded to other treatments, but these ointments have an unpleasant odor and stain clothing.

Patients who have stasis dermatitis should elevate their legs as often as possible and sleep with a pillow between the lower legs.

Tar or zinc paste may also be used to treat stasis dermatitis. Because these compounds must remain in contact with the rash for as long as two weeks, the paste and bandages must be applied by a nurse or a doctor.

Coal-tar shampoos may be used for seborrheic dermatitis that occurs on the scalp. Sun exposure after the use of these shampoos should be avoided because the risk of sunburn of the scalp is increased.

Alternative treatment

Some herbal therapies can be useful for skin conditions. Among the herbs most often recommended are:

Contact dermatitis can be treated botanically and homeopathically. Grindelia (Grindelia spp.) and sassafras (Sassafras albidum) can help when applied topically. Determining the source of the problem and eliminating it is essential. Oatmeal baths are very helpful in relieving the itch. Bentonite clay packs or any mud pack draws the fluid out and helps dry up the lesions. Cortisone creams are not recommended.

Stasis dermatitis should be treated by a trained practitioner. This condition responds well to topical herbal therapies, however, the cause must also be addressed. Selenium-based shampoos, topical applications of flax oil and/or olive oil, and biotin supplementation are among the therapies recommended for seborrheic dermatitis.

Prognosis

Dermatitis is often chronic, but symptoms can generally be controlled.

Prevention

Contact dermatitis can be prevented by avoiding the source of irritation. If the irritant cannot be avoided completely, the patient should wear gloves and other protective clothing whenever exposure is likely to occur.

Immediately washing the exposed area with soap and water can stem allergic reactions to poison ivy, poison oak, or poison sumac, but because soaps can dry the skin, patients susceptible to dermatitis should use them only on the face, feet, genitals, and underarms.

Clothing should be loose fitting and 100% cotton. New clothing should be washed in dye-free, unscented detergent before being worn.

Injury to the lower leg can cause stasis dermatitis to ulcerate (form open sores). If stasis ulcers develop, a doctor should be notified immediately.

Yoga and other relaxation techniques may help prevent atopic dermatitis caused by stress.

Avoidance of sweating may aid in preventing seborrheic dermatitis.

A patient who has dermatitis should also notify a doctor if any of the following occurs:

Resources

Other

"Allergic Contact Dermatitis." The Skin Site. April 10, 1998 (January 11, 2006). http://www.skinsite.com/info_allergic.htm.

Key terms

Allergic reaction — An inappropriate or exaggerated genetically determined reaction to a chemical that occurs only on the second or subsequent exposures to the offending agent, after the first contact has sensitized the body.

Corticosteriod — A group of synthetic hormones that are used to prevent or reduce inflammation. Toxic effects may result from rapid withdrawal after prolonged use or from continued use of large doses.

Patch test — A skin test that is done to identify allergens. A suspected substance is applied to the skin. After 24-48 hours, if the area is red and swollen, the test is positive for that substance. If no reaction occurs, another substance is applied. This is continued until the patient experiences an allergic reaction where the irritant was applied to the skin.

Rash — A spotted, pink or red skin eruption that may be accompanied by itching and is caused by disease, contact with an allergen, food ingestion, or drug reaction.

Ulcer — An open sore on the skin, resulting from tissue destruction, that is usually accompanied by redness, pain, or infection.

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dermatitis /der·ma·ti·tis/ (der?mah-ti´tis) pl. dermati´tides   inflammation of the skin.

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actinic dermatitis  dermatitis due to exposure to actinic radiation, such as that from the sun, ultraviolet waves, or x- or gamma radiation.

allergic dermatitis 

1. atopic d.

2. allergic contact d.

allergic contact dermatitis  contact dermatitis due to allergic sensitization.

ammonia dermatitis  diaper dermatitis attributed to skin irritation, due to the ammonia decomposition products of urine.

atopic dermatitis  a chronic inflammatory, pruritic, eczematous skin disorder in individuals with a hereditary predisposition to cutaneous pruritus; often accompanied by allergic rhinitis, hay fever, and asthma.

berlock dermatitis , berloque dermatitis dermatitis of the neck, face, or chest, with patches or streaks, caused by exposure to perfume or other toilet articles containing bergamot oil and then to sunlight.

cercarial dermatitis  swimmers' itch.

contact dermatitis  acute or chronic dermatitis caused by substances contacting the skin; it may involve allergic or nonallergic mechanisms.

diaper dermatitis  diaper rash.

dermatitis exfoliati´va neonato´rum  staphylococcal scalded skin syndrome.

exfoliative dermatitis  virtually universal erythema, desquamation, scaling, and itching of the skin, with loss of hair.

dermatitis herpetifor´mis  pruritic chronic dermatitis with successive groups of symmetrical, erythematous, papular, vesicular, eczematous, or bullous lesions, usually associated with asymptomatic gluten-sensitive enteropathy.

infectious eczematous dermatitis  a pustular eczematoid eruption arising from a primary lesion that is the source of an infectious exudate.

insect dermatitis  a transient skin eruption caused by the toxin-containing irritant hairs of insects such as certain moths and their caterpillars.

irritant dermatitis  a nonallergic type of contact dermatitis due to exposure to a substance that damages the skin.

livedoid dermatitis  local pain, swelling, livedoid changes, and increased temperature; due to temporary or prolonged local ischemia from vasculitis or from accidental arterial obliteration during intragluteal administration of medications.

meadow dermatitis , meadow-grass dermatitis phytophotodermatitis with eruption of vesicles and bullae in streaks or other configurations, caused by exposure to sunlight after contact with meadow grass.

photoallergic contact dermatitis , photocontact dermatitis allergic contact dermatitis caused by the action of sunlight on skin sensitized by contact with substances such as halogenated salicylanilides, sandalwood oil, or hexachlorophene.

phototoxic dermatitis  erythema followed by hyperpigmentation of sun-exposed areas of the skin, due to exposure to agents containing photosensitizing substances, such as coal tar and psoralen-containing perfumes, drugs, or plants, and then to sunlight.

poison ivy dermatitis , poison oak dermatitis, poison sumac dermatitis allergic contact dermatitis due to exposure to plants of the genus Rhus, which contain urushiol, a skin-sensitizing agent.

radiation dermatitis  radiodermatitis.

rat mite dermatitis  that due to a bite of the rat-mite, Ornithonyssus bacoti.

dermatitis re´pens  acrodermatitis continua.

rhus dermatitis  poison ivy, poison oak, or poison sumac d.

schistosome dermatitis  swimmer's itch.

seborrheic dermatitis , dermatitis seborrhe´ica chronic pruritic dermatitis with erythema, scaling, and yellow crust on areas such as the scalp, with exfoliation of excessive dandruff.

stasis dermatitis  chronic eczematous dermatitis due to venous insufficiency, initially on the inner aspect of the lower leg above the internal malleolus, sometimes spreading over the lower leg, marked by edema, pigmentation, and often ulceration.

swimmers' dermatitis  see under itch.

uncinarial dermatitis  ground itch.

x-ray dermatitis  radiodermatitis.

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der·ma·ti·tis (dûrm-tts)

n. pl. der·ma·ti·tis·es or der·ma·tit·i·des (-tt-dz)

Inflammation of the skin.

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dermatitis,

n inflammatory skin condition. Severity, duration, and treatment depend on the type (i.e., contact dermatitis and actinic dermatitis).

Dermatitis.

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dermatitis (durmtī´tis),

n an inflammation of the skin.

dermatitis, allergic contact,

n the reaction of the skin to direct contact with a specific antigen. Poison ivy rash is a common example of an allergic contact dermatitis.

dermatitis, atopic

(ātō´pik),
n an atopic eczema characterized by the distinctive phenomenon of atopy, a familial related allergic response associated with IgE antibody.

dermatitis, contact,

n a delayed type of induced sensitivity (allergy) of the skin with varying degrees of erythema, edema, and vesiculation, resulting from cutaneous contact with a specific allergen. It is an occupational hazard in dentistry.

dermatitis herpetiformis

n dermatitis characterized by grouped, erythematous, papular, vesicular, pustular, or bullous lesions occurring in various combinations, often accompanied by vesicobullous and ulcerative lesions of the oral mucosa.

dermatitis infectiosa eczematoides (Engman's disease),

n a pustular eczematous eruption that frequently follows or occurs coincidentally with some pyogenic process.

dermatitis, occupational,

n a contact dermatitis associated with allergens found in the workplace.

dermatitis, radiation,

n an inflammation of the skin resulting from a high dose of radiation. The reaction varies with the quality and quantity of radiation used and is usually transitory.

dermatitis, seborrheic

n a chronic inflammatory skin disease that can affect the scalp, face, ears, armpits, breasts, and groin. Its symptoms include moist, greasy, or dry scaling and patches of yellowish crust. Although the cause is unknown, it can be treated with selenium sulfide shampoos, topical antibiotics, and topical and oral corticosteroids.

Dermatitis.

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dermatitis

inflammation of the skin. Dermatitis can result from various animal, vegetable and chemical substances, from heat or cold, from mechanical irritation, from certain forms of malnutrition, or from infectious disease.

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actinobacillary dermatitis

rare disease in cattle; large ulcers discharging yellow pus or nodules, on lymphatics with local lymph node enlargement.

acute moist dermatitis

a superficial bacterial infection of the skin, usually caused by self-trauma, i.e. scratching, rubbing, biting. In dogs, ectoparasites, otitis, anal sacculitis and pruritic skin diseases are common precipitating causes. Affected skin is moist, weeping, and has a covering of matted haircoat and dried exudate. Staphylococcus spp. are usually present. Called also pyotraumatic dermatitis, 'hot spots'.

allergic contact dermatitis

see allergic contact dermatitis.

allergic inhalant dermatitis

see canine atopy.

atopic dermatitis

see canine atopy.

cercarial dermatitis

see trichobilharzia.

cheyletiella dermatitis

see cheyletiella.

contagious pustular dermatitis of sheep

see contagious ecthyma.

coronet dermatitis

part of several infectious mucosal diseases of cattle; also in equine pemphigus.

dermatitis crustosa

exudative epidermitis.

elaeophorial dermatitis

see elaeophoriasis.

equine contagious pustular dermatitis

see canadian horsepox.

equine exfoliative eosinophilic dermatitis

characterized by infiltration of eosinophils and granulomatous inflammation with ulcerative stomatitis and wasting; suspected of being a hypersensitivity to Strongylus equinus larvae.

equine staphylococcal dermatitis

see equine staphylococcal dermatitis.

exudative dermatitis of pigs

see exudative epidermitis.

feline miliary dermatitis

a papular, crusting skin disease located predominantly on the back, with varying degrees of pruritus. Ectoparasites, food and drug allergy, and infection by fungi or bacteria are among the many possible causes. Called also scabby cat disease.

feline psychogenic dermatitis

see idopathic hyperesthesia syndrome.

feline solar dermatitis

see solar dermatitis (below).

fibrosing dermatitis

dermatitis sufficiently severe to affect deep layers of the dermis results in scarring of the skin due to excessive fibrous tissue formation.

filarial dermatitis

see stephanofilarosis, onchocercosis.

fold dermatitis

moisture, friction and secondary infection in body folds such as facial fold in brachycephalic dog breeds, tail fold in dog breeds with extremely short, often screw, tails, lip fold in spaniel breeds, perivulvar fold in obese bitches, and all over the body in the Shar pei.

Nasal fold dermatitis in a Bulldog. By permissionfrom Kummel BA, Color Atlas of Small Animal Dermatology,Mosby, 1989

grain itch mite dermatitis

a transient, superficial dermatitis, mostly about the head in horses; may be all over the body in pigs. Caused by pediculoides ventricosus or tyroglyphus.

granular dermatitis

swamp cancer.

dermatitis herpetiformis

chronic dermatitis in humans marked by successive crops of grouped, symmetrical, erythematous, papular, vesicular, eczematous or bullous lesions, accompanied by itching and burning; a granular deposition of IgA immunoglobulin around the lesion almost always occurs. Occurs rarely in dogs.

idiopathic caprine dermatitis

alopecic, exudative dermatitis of pygmy goats.

infectious dermatitis of piglets

see contagious porcine pyoderma.

inhalant dermatitis

see canine atopy.

interdigital dermatitis

see interdigital dermatitis.

interface dermatitis

a histopathological pattern of inflammatory skin disease with the dermoepidermal junction obscured by hydropic degeneration and/or lichenoid cellular infiltrate.

intertriginous dermatitis

see fold dermatitis (above).

intraepidermal pustular dermatitis

see equine allergic dermatitis.

lipfold dermatitis

see fold dermatitis (above).

Malassezia dermatitis

a pruritic, seborrheic skin disease of dogs, particularly some breeds including West Highland white terriers, Shetland sheepdogs, Poodles, and Cocker spaniels, and rarely cats, caused by colonization of the skin by the yeast, Malassezia pachydermatis. There is usually an underlying cause such as atopy or bacterial pyoderma.

mammary pustular dermatitis

see mammary pustular dermatitis.

dermatitis medicamentosa

an eruption or solitary skin lesion caused by a drug taken internally.

miliary dermatitis

see feline miliary dermatitis (above).

moist dermatitis of rabbits

the rabbit's pendulous dewlap keeps getting wet and develops a moist dermatitis as a result. Called also slobbers, wet dewlap.

mycotic dermatitis

see mycotic dermatitis.

nasal solar dermatitis

see solar dermatitis (below), collie nose.

ovine interdigital dermatitis

see ovine footrot.

ovine staphylococcal dermatitis

ulcerative dermatitis of the face of adult sheep and young lambs caused by a dermatopathic strain of Staphylococcus aureus. Called also ovine staphylococcal pyoderma.

pastern dermatitis

see greasy heel.

pelodera dermatitis

caused by larvae of the free-living nematode Pelodera strongyloides and characterized by alopecia, itching, thick, scurfy skin and 0.5 inch diameter pustules which contain the larvae.

photocontact dermatitis

allergic contact dermatitis caused by the action of sunlight on skin sensitized by contact with a substance capable of causing this reaction.

photosensitive dermatitis

see photosensitive dermatitis.

plastic dish dermatitis

a contact dermatitis caused by plastic feeding dishes to which a dog is allergic.

porcine juvenile pustular psoriasiform dermatitis

see pityriasis rosea.

potato dermatitis

see potato dermatitis.

primary-irritant dermatitis

contact dermatitis (see above) induced by a substance acting as an irritant rather than as a sensitizer or allergen.

proliferative dermatitis

see strawberry footrot.

psoriaform, psoriasiform dermatitis of swine

see pityriasis rosea.

pyotraumatic dermatitis

see acute moist dermatitis (above).

dermatitis-pyrexia-hemorrhage syndrome

a pruritic, papulocrustous dermatitis in dairy cows which is accompanied by fever and hemorrage from the nose and anus. It is believed to be caused by a toxin.

rhabditic dermatitis

see pelodera dermatitis (above).

seasonal allergic dermatitis

see atopy, equine allergic dermatitis.

seborrheic dermatitis, dermatitis seborrheica

a chronic, usually pruritic, dermatitis with erythema, dry, moist or greasy scaling, and yellow crusted patches on various areas, with exfoliation of an excessive amount of dry scales (dandruff) or encrustations of sebum on the skin. See also exudative epidermitis (pigs), greasy heel (horses), flexural seborrhea (cows).

solar dermatitis

a chronic, inflammatory reaction on white or lightly pigmented and exposed skin caused by sunlight. Most commonly seen on the ear tips, nose and eyelids of white cats and the nose of collie dogs or related breeds. Squamous cell carcinomas sometimes develop in affected skin. Called also nasal solar dermatitis, actinic dermatitis. See also collie nose.

spongiotic dermatitis

perivascular inflammation with spongiosis.

summer dermatitis

see equine allergic dermatitis.

superficial pustular dermatitis

immature dogs may develop pustules on the inguinal or axillary skin, often in association with poor nutrition, systemic infection, or parasitism. In kittens, these may occur on the neck, caused by 'mouthing' by the queen.

trefoil dermatitis

see trefoil dermatitis.

tyroglyphid dermatitis

see tyroglyphus.

unilateral papular dermatitis

a disease of horses characterized by the appearance of many nodules or papules on one side of the neck and body. The lesions are eosinophilic folliculitis and perifolliculitis. The etiology and the unilateral distribution of the lesions are unexplained.

ventral midline dermatitis

small ulcers with hemorrhagic crusts and hair loss, located on the abdomen, particularly around the umbilicus, of horses; caused by biting flies and gnats.

vesicular dermatitis

see avian vesicular dermatitis.

viral contagious dermatitis

see contagious ecthyma.

viral papular dermatitis

see equine papular dermatitis.

x-ray dermatitis

radiodermatitis.