allergic contact dermatitis

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al·ler·gic con·tact der·ma·ti·tis

a delayed type IV allergic reaction of the skin with varying degrees of erythema, edema, and vesiculation resulting from cutaneous contact with a specific allergen.
Synonym(s): contact allergy

allergic contact dermatitis

allergic contact dermatitis

A condition caused by cell-mediated immunity due to contact with haptens (e.g., nickel, chromates, ursodiols) in poison ivy and poison oak, synthetic chemicals, drugs, cosmetics, jewelry, neomycin ointment, etc., which may affect any body part.

Clinical findings
Often intense pruritus; erythema; intercellular oedema; papulovesicles, which with continued exposure are followed by vesiculation, rupture and oozing dermatitis.
Modifying factors—host
Genetic predisposition, age, route of 1º sensitisation, concomitant disease (e.g., immunocompromised, as in AIDS).
Modifying factors—environment
Physicochemical modulation.

Patch test.
Topical steroids.

allergic contact dermatitis

Allergic dermatitis Dermatology A condition caused by cell-mediated immunity due to contact with haptens–eg, nickel, chromates, ursodiols in poison ivy and poison oak, synthetic chemicals, drugs, cosmetics, jewelry, neomycin ointment, etc, and may affect any body part Clinical Intense pruritus, erythema, intercellular edema, papulovesicles, which with continued exposure, are followed by vesiculation, rupture and oozing dermatitis Modifying factors–host Genetic predisposition, age, route of 1º sensitization, and concomitant disease–eg, immunocompromise as in AIDS Modifying factors–environment Physicochemical modulation. Diagnosis Patch test Management Topical corticosteroids. See Contact dermatitis, Patch test.

al·ler·gic con·tact der·ma·ti·tis

(ă-lĕr'jik kon'takt dĕr'mă-tī'tis)
A delayed type IV allergic reaction of the skin with varying degrees of erythema, edema, and vesiculation resulting from cutaneous contact with a specific allergen.
Synonym(s): contact allergy.


(der?ma-tit'is ) (-tit'i-dez?) plural.dermatitidesplural.dermatitises [ dermato- + -itis]
An inflammatory rash marked by itching and redness. See: eczema


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.


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.

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actinic dermatitis

A chronic red or eczematous rash, usually on the face or exposed skin surfaces, that typically results from exposure and sensitization to ultraviolet rays. Adults over age 50 may be affected. See: illustration Synonym: photosensitivity dermatitis

allergic contact dermatitis

Contact dermatitis.
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atopic dermatitis

Chronic dermatitis of unknown cause found in patients with a history of allergy. The disease usually begins after the first 2 months of life, and those affected may experience exacerbations and remissions throughout childhood and adulthood. In many cases, there is a family history of allergy or atopy: if both parents have atopic dermatitis, the chances are nearly 80% that their children will have it, as well. Atopic dermatitis is typically found in flexural creases of the body, e.g., the antecubital and popliteal fossae. The skin lesions consist of reddened, cracked, and thickened skin that can become exudative and crusty from scratching. Scarring or secondary infection may occur. Most patients have an elevated level of immunoglobulin E in their serum. See: illustration


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.


berloque dermatitis

, berlock dermatitis
A type of phytophotodermatitis with postinflammatory hyperpigmentation at the site of application of perfumes or colognes containing oil of bergamot.
Synonym: bergamot phototoxicity.

dermatitis calorica

Inflammation due to heat, as in sunburn, or cold.

cercarial dermatitis

Swimmer's itch.
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CONTACT DERMATITIS: Allergic reaction to topical anesthetic

contact dermatitis

Dermatitis 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: illustration


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.


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


contagious pustular dermatitis

A cutaneous disease of sheep and goats transmitted to humans by direct contact. The lesion on humans is usually solitary and on the hands, arms, or face. This maculopapular area may progress to a pustule up to 3 cm in diameter and may last 3 to 6 weeks. The etiological agent is Parapoxvirus, , a genus of poxvirus.
Synonym: orf

diaper dermatitis

Diaper rash.

exfoliative dermatitis

Generalized dermatitis, often followed by scaling. It may be caused by leukemias or lymphomas that infiltrate the skin; extensive psoriasis; drug reactions (such as vancomycin); allergies, seborrhea, or atopy. The condition is often associated with systemic findings, including lymphadenopathy, hepatic and splenic enlargement, fever, anemia, eosinophilia, and decreases in serum albumin.

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


Therapy is directed at treating the underlying cause.

factitial dermatitis

A self-inflicted irritation or injury to the skin.

dermatitis herpetiformis

A chronic dermatitis characterized by erythematous, papular, vesicular, bullous, or pustular lesions with a tendency to grouping and with intense itching and burning.


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


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.


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

dermatitis hiemalis

Winter itch.

dermatitis infectiosa eczematoides

A pustular eruption during or following a pyogenic disease.

livedo-like dermatitis

Nicolau syndrome.

meadow dermatitis

A blistering rash that appears on the exposed skin of hikers, florists, gardeners, and those who work outdoors in bright sunlight. It is a phototoxic reaction caused by exposure to light-sensitizing chemicals in some plants (such as parsley, rue, bergamot, and fig).

dermatitis medicamentosa

Drug rash.

dermatitis multiformis

A form of dermatitis with pustular lesions.

dermatitis papillaris capillitii

Formation on the scalp and neck of papules interspersed with pustules. The rash ultimately produces scarlike elevations resembling keloids.

photoallergic contact dermatitis


photosensitivity dermatitis

Actinic dermatitis.

poison ivy dermatitis

Dermatitis resulting from irritation or sensitization of the skin by urushiol, the toxic resin of plants of the genus Toxicodendron (Rhus). There is no absolute immunity; susceptibility varies greatly, even in the same individual.

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.


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.


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


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.


primary dermatitis

Dermatitis that is a direct rather than an allergic response.

radiation dermatitis

Dermatitis due to radiation exposure.
Synonym: radioepidermitis; radioepithelitis; radiodermatitis

rhus dermatitis

Contact dermatitis caused by the toxic resin in poison ivy or oak.
See: poison ivy dermatitis; Toxicodendron

schistosome dermatitis

Swimmer's itch.

dermatitis seborrheica

An acute or subacute dermatitis of unknown cause, beginning on the scalp and/or face and in skin folds (any area where sebaceous glands are active) and characterized by rounded, irregular, or circinate lesions covered with yellow or brown-gray greasy scales. Synonym: pityriasis capitis; seborrhea corporis; seborrhea sicca


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.


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.

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stasis dermatitis

Eczema of the legs with edema, pigmentation, and sometimes chronic inflammation. It is usually due to impaired return of blood from the legs. Compression stockings help the rash to resolve gradually. See: illustration

dermatitis venenata

1. Contact dermatitis.
2. Any inflammation caused by local action of various animal, vegetable, or mineral substances contacting the surface of the skin.

dermatitis verrucosa

A chronic fungal infection of the skin characterized by the formation of wartlike nodules. These may enlarge and form papillomatous structures that sometimes ulcerate.


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

al·ler·gic con·tact der·ma·ti·tis

(ă-lĕr'jik kon'takt dĕr'mă-tī'tis)
Delayed type IV allergic reaction of the skin with varying degrees of erythema, edema, and vesiculation resulting from cutaneous contact with a specific allergen.


pertaining to or caused by allergy.

allergic alveolitis
allergic breakthrough
a theory which attributes temporary increases in clinical severity of atopy to influences, such as concurrent disease or hormonal variations, acting to inhibit the mechanisms which normally regulate production of IgE at low levels following sensitization.
allergic bronchitis
see bronchitis, feline bronchial asthma, pie syndrome.
allergic contact dermatitis
results from percutaneous sensitization to allergens, usually haptens, that form covalent bonds with epidermal proteins, and the development of a delayed (type IV) hypersensitivity. Lesions typically correspond in location to the area of contact between allergen and skin which in animals is often in relatively hairless areas unless the allergen is presented in liquid form.
allergic dermatitis
inflammation of the skin resulting from exposure to antigens to which the animal is hypersensitive. Usually involving immediate (type I) hypersensitivity but also commonly applied to reactions involving delayed (type IV) hypersensitivity. The specific skin reaction, lesions and pattern of disease produced depend on many factors including the type of allergen and immune mechanism, route of exposure and species differences. See also atopy, sweet itch, allergic contact dermatitis (above).
allergic encephalitis
see experimental allergic encephalomyelitis.
equine allergic dermatitis
an intensely itchy dermatitis along the back of horses caused by sensitivity to the bites of the sandfly Culicoides brevitarsus and possibly other insects. Called also sweet itch, Queensland itch.
allergic inhalant dermatitis
see atopy.
allergic reaction
an immune-mediated, adverse clinical response, following the inhalation, ingestion or injection of an antigen by a sensitized animal. Manifestations include urticaria or anaphylaxis.
allergic rhinitis
see enzootic nasal granuloma, summer snuffles.
allergic urticaria


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.

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
cheyletiella dermatitis
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
equine contagious pustular dermatitis
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
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.
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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
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
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