Contact dermatitis

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Refers to a rash resulting from skin reactions, a type of skin inflammation.

Results from exposure to allergens that can result in allergic contact dermatitis or irritants resulting in irritant contact dermatitis.

Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight.

A localized rash or irritation of the skin caused by contact with a foreign substance.

Only the superficial regions of the skin are affected, with inflammation present in the epidermis and the outer dermis.

Results in burning, and itchy rashes.

Can take from several days to weeks to heal, and resolves only if the skin no longer in contact with the allergen or irritant.

Chronic contact dermatitis can result when the removal of the offending agent no longer provides improvement.

Common causes of allergic contact dermatitis include: nickel, gold, chromium. poison ivy, poison oak, poison sumac, Grevillea sp,, Ginka biloba fruits,

Common irritant causes of contact dermatitis include: solvents, metalworking fluids, latex, kerosene, ethylene oxide, certain foods and drink, food flavorings, spices, perfumes, topical surfactants in medications and cosmetics, alkalis, low humidity environments, plants, alkaline soaps, detergents, and cleaning products.

The three types of contact dermatitis are: irritant contact dermatitis; allergic contact dermatitis; and photocontact dermatitis.

Photocontact dermatitis is divided into two categories: phototoxic and photoallergic.

Irritant contact dermatitis can be divided into forms caused by chemical irritants, and those caused by physical irritants.

Common chemical irritants include: solvents such alcohol, xylene, turpentine, esters, acetone, and ketones, metalworking fluids, latex, kerosene; ethylene oxide, surfactants in topical medications and cosmetics, and alkalis such as drain cleaners, and strong soap with lye residues.

Physical irritant contact dermatitis most commonly be caused by low humidity from air conditioning, and plants that can irritate the skin.

Allergic contact dermatitis (ACD) is the most prevalent form of immunotoxicity found in humans, and is a common occupational and environmental health problem.

Allergic contact dermatitis is a hypersensitive reaction, with interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes.

Allergens include: nickel, gold, Balsam of Peru, chromium, and the oily coating from plants of the Toxicodendron genus: poison ivy, poison oak, and poison sumac.

Photocontact dermatitisis divided into two categories, phototoxic and photoallergic

Photocontact dermatitisis is the eczematous condition triggered by an interaction between an otherwise unharmful or less harmful substance on the skin and ultraviolet light (320–400 nm UVA), so that without the presence of these rays, the photosensitiser is not harmful.

This form of contact dermatitis is usually associated only with areas of skin which are left uncovered by clothing, and the mechanism of action is usually due to the production of a photoproduct.

Photocontact dermatitis associated with psoralen toxins, which are used therapeutically for the treatment of psoriasis, eczema, and vitiligo.

Allergic dermatitis is usually confined to the area where the trigger actually touched the skin.

Irritant dermatitis may be more widespread on the skin than allergic dermatitis.

Red rash usually appears immediately in irritant contact dermatitis.

In allergic contact dermatitis, the rash sometimes does not appear until 24–72 hours after exposure to the allergen.

Blisters, wheals and urticaria often form in a pattern where skin was directly exposed to the allergen or irritant.

Irritant contact dermatitis tends to be more painful than itchy, while allergic contact dermatitis often itches.

Irritant contact dermatitis often affects the hands, which have been exposed to the irritant.

Management for blistering includes cold moist compresses13] applied to offer relief.

Calamine lotion may relieve itching.

Oral antihistamines can relieve itching.

Scratching is to be avoided.

After exposure to a known allergen or irritant, immediate washing with soap and cool water to remove or inactivate the offending substance.

For mild cases in a small area hydrocortisone cream in nonprescription strength may be sufficient.

Weak acid solutions such as lemon juice, or vinegar can be used to counteract the effects of dermatitis contracted by exposure to basic irritants.

A barrier cream, such as those containing may help protect the skin and retain moisture.

Medical treatment usually consists of lotions, creams, or oral medications.

A corticosteroid may be prescribed to combat inflammation in a localized area.

If the dermatitis covers a large area of the skin or is severe, a systemic corticosteroid may be prescribed.

It is important to identify the responsible agent and avoid it, and this can be accomplished by having patch tests, one of various methods commonly known as allergy testing.

The top three allergens found in patch tests are: nickel sulfate (19.0%), Myroxylon pereirae (Balsam of Peru, 11.9%), and fragrance mix I (11.5%).

Topical antibiotics should not be used to prevent infection in wounds after surgery as such persons recovering from surgery is at significantly increased risk of developing contact dermatitis.