Contact dermatitis is a reaction, which occurs when skin comes in contact with certain substances. Two mechanisms exist by which substances can cause skin inflammation - Irritation (Irritant contact dermatitis) or Allergic reaction (Allergic contact dermatitis). Common irritants include soap, detergents, acids, alkalis and organic solvents (as are present in nail varnish remover). Contact dermatitis is most often seen around the hands or areas that touched or were exposed to the irritant/allergen. Contact dermatitis of the feet also exists but differs in that it is due to the warm, moist conditions in the shoes and socks. An allergic reaction does not generally occur the first time one is exposed to a particular substance but on subsequent exposures, which can cause dermatitis in 4 to 24 hours. Treatment includes removal or avoidance of the substance causing the irritation and cleansing the area with water and mild soap (to avoid infection). A recent recommendation for mild cases is to use a manganese sulfate solution to reduce the itching. Antihistamines are generally not very helpful for treatment of contact dermatitis. Another common treatment for severe contact dermatitis is with corticosteroid tablets, ointments or creams, which diminish the immune attack and resulting inflammation. Corticosteroids will not cure the problem. Overuse, misuse and/or prolonged use of steroids can worsen the problem or create an even more difficult condition. Never use steroids on the face. 

Many laundry soaps contain chemical additives which are the actual irritants (e.g., sodium silicate, sodium phosphate, sodium carbonate). Hand cleaner soaps contain small harsh particles to assist in grease removal, such as pumice, talc, borax, corn meal or wood flour. These are sometimes irritating. Some yellow laundry soaps contain "rosin" to make the bar more soluble, which is also a sensitizer.

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:

• Chlorine
• Cleansers
• Detergents and soaps
• Fabric softeners
• Glues used on artificial nails
• Perfumes
• Topical medications.

Allergic contact eczema (dermatitis) is a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions. Red, bumpy, scaly, itchy, and swollen skin are all symptoms which can signify an allergic skin condition. These skin problems are often caused by an immune system reaction, signifying an allergy. Allergic skin conditions can take several forms and are due to various causes.

Toxicodendron dermatitis, also called Allergic phytodermatitis or Rhus dermatitis is an allergic contact dermatitis that occurs from exposure to members of the plant genus Toxicodendron. In North America , this includes poison ivy, poison oak, and, much less frequently, poison sumac. Usually the skin is involved; however, the eyes, airway, and lungs may be involved if exposed to smoke from burning plants. In susceptible individuals, lesions generally appear within 12-24 hours, although they have been noted to arise earlier. New lesions may continue to appear for up to 2-3 weeks.

Nickel Allergy - Contact allergic dermatitis to nickel may develop at any age. Once this nickel allergy has occurred, it persists for many years, often life-long. Nickel allergy is more common in women, probably because they are more likely to have pierced ears than men, although this is changing. The degree of allergy varies. Some people develop dermatitis (also called eczema) from even brief contact with nickel-containing items, while others break out only after many years of skin contact with nickel.

In jewelry - necklaces, necklace-clips, earrings, bracelets, watch-straps and rings may contain nickel. "Hypoallergenic", solid gold (12 carat or more) and silver jewelry should be safe. Nine carat gold and white gold both contain nickel. Plastic covers for earring studs can be obtained. Coating the stud with nail varnish is not recommended

In clothing - metal zips, bra hooks, suspender clips, hair-pins, buttons, studs, spectacle frames etc. are likely to contain nickel. Use substitutes made of plastic, coated or painted metal or some other material.

Consider lipstick holders, powder compacts, handbag catches, cigarette lighters, razors, keys, key rings, pocket knives, pens as potential causes of nickel dermatitis.

Metal items in the home such as cupboard handles, kitchen utensils, cutlery, toaster, metal teapots, scissors, needles, pins, thimble, vacuum cleaners, torches, bath plugs... may all contain nickel. Choose tools with plastic handles. Stainless steel does not usually cause dermatitis unless it is nickel-plated.

Silver coins are composed of cupro-nickel. Cashiers with nickel allergy may develop hand dermatitis from this source. Wear gloves to handle money or pay with a credit card or check

Nickel dermatitis may also be aggravated by contact with paper clips, typewriter keys, instruments, or metal fragments from a lathe or chain saw.

Hives or urticaria are red, itchy, swollen areas of the skin that can range in size and appear anywhere on the body. Most common are acute cases of hives, where the cause is identifiable—often a viral infection, drug, food or latex. These hives usually go away spontaneously. Some people have chronic hives that occur almost daily for months to years. For these individuals, various circumstances or events, such as scratching, pressure or "nerves," may aggravate their hives. However, eliminating these triggers has little effect on this condition.

Angioedema, a swelling of the deeper layers of the skin, sometimes occurs with hives. Angioedema is not red or itchy, and most often occurs in soft tissue such as the eyelids, mouth or genitals. Hives and angioedema may appear together or separately on the body. Hives are caused by a chemical called histamine and are responsible for many of the symptoms of allergic layers of the skin. Angioedema results from the actions of these chemicals in the deeper layers of the skin. These chemicals are usually stored in our bodies’ mast cells, which are cells heavily involved in allergic reactions. There are several identifiable triggers that release histamine and other chemicals from the mast cells, causing hives.

In adults, reactions to medicines are a common cause of acute hives. Medications known to cause hives or angioedema include aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, high blood pressure medicines known as ACE-inhibitors, or pain-killers containing codeine or codeine-like drugs. Like all drug-induced hives, these reactions occur within only minutes to an hour of taking the drug. Adults can also develop hives after eating certain foods, including nuts, eggs, shellfish, soy, wheat or milk—the culprits in more than 90% of proven food-induced hives. In children, foods or viral infections such as a cold can trigger acute hives. Physical urticaria is hives resulting from an outside source: rubbing of the skin, cold, heat, physical exertion or exercise, pressure or direct exposure to sunlight. Patients with chronic hives often report that at least one of these triggers induces their hives.

Whenever there is an identifiable trigger of hives, it should be eliminated. In patients with acute hives, some drugs or foods may take days to be eliminated from the body.

CONTACT DERMATITIS - SENSITIZER TYPE                        

An allergic contact dermatitis can be caused by fabric finishes, dyes, oils, tars, rubber, soap, cosmetics and perfume, insecticides, wood resins, plants, paints, plastics, glues, fiber glass, metals, polishes, ointments (home remedies) and occupational hazards (e.g., lithographers).

The sensitization type of allergic contact dermatitis usually occurs anywhere from 5 to 7 days and occasionally as long as 20 days after the initial or sensitizing contact, at the site of contact. There are no circulatory or otherwise detectable antibodies produced, although there is a local tissue allergy. This condition is usually, though not invariably life-long. The most common sensitizers are plants, paraphyenylenediamine, nickel, rubber components and the dichromates.

CONTACT DERMATITIS - COSMETICS DERMATITIS        

Most commonly occurs from hair dyes, nail polishes, perfumes, lipsticks and sunscreen agents. The chief site of the eruption is the eyelids area, with ears and neck next.

Eye makeup, such as mascara, eye shadow and eye pencil, seldom causes dermatitis (although eyeliner often does) whereas nail polish, while seldom causing trouble around the fingernails, affects the eyelids first. Lower eyelid dermatitis is often form wetting solutions or eye drops. Various formaldehyde resins are used in nail lacquers and nail lacquers and nail hardeners, as are sulfonamide derivatives, both of which sensitize.

Lipsticks contain waxes and fats (occasionally cocoa butter sensitizes), perfumes (occasionally sensitize), and dyes (especially tetrabromofluorescein), which may occasionally dry the lips and produce photosensitivity. Special lipsticks are available which contain neither fluorescent dyes, nor perfumes, like, such as, Almay (Texas Pharmacal) or Ar-Ex.

Sunscreen preparations containing PABA (para-aminobenzoic acid), hydroquinone or digalloy trioleate can sensitize, and in some cases, photosensitize. Bleaching creams are sensitizers too, either mercury, or hydroquinone being the culprit.

Toothpaste and mouthwashes can cause dermatitis from oils, cinnamon or other flavoring, or antiseptics. This is called peri-oral dermatitis. Using a non-tartar, non-fluoride toothpaste can often help in these cases.

Hair dyes are mostly of the permanent or "oxidation" type, containing para-phenylene diamine (PPDA), soap, ammonia and other modifiers which penetrate and color the hair when mixed with 20 volumes of peroxide. This type of dye accepts shampoos and cold waves and sensitizes most commonly. The azo and aniline dyes produce a semi-permanent coloring which is tolerated well in most PPDA-sensitive patients, but lasts through only a few washings. Metallic hair dyes (Romans used a lead comb dipped in vinegar to darken gray hair) are also referred to as hair "restorers" and are mostly still based on lead and do not sensitize. Vegetable rinses are usually made form henna, which is non-sensitizing, although some pyrogallol combinations are sensitizing. Methylene PPDA can cross-react with PABA in sunscreens, local anesthetics and sulfonamides-thiazides (Diruil), tolbutamide (Orinase), chlorpropamide (Diabinase) and saccharin.

Permanent-wave solutions, usually thioglycolates, are alkaline reducing agents which make the hair malleable; the hair is "waved" on rollers and then "fixed" with an oxidizer (hydrogen peroxide, perborate, bromates of citric acid). Thioglycolates rarely sensitize, but do occasionally cause primary irritation if not carefully mopped up, and can split and break the hair.

The adhesive used to attach toupees and false eyelashes occasionally cause dermatitis. Bleaching or freckle creams usually contain mercury or quinones, and all can sensitize; Benzoquin (Elder) is a very potent sensitizer. Face powders and rouge rarely cause dermatitis. For toupees and ileostomy stoma irritated by other rubber cements, Duo brand surgical adhesive (Johnson & Johnson) is well tolerated by many.

People should be advised to apply perfume to their clothes if possible rather than to their skin and certainly should avoid using photosensitizing perfumes (one such example is Shalimar) on their skin in bright sun.

Contact Dermatitis-Rubber Fully finished and polymerized plastics seldom cause an allergic contact dermatitis, whereas fully "cured" rubber articles do so quite frequently. Of the antioxidants used to prolong the life of the rubber, monobenzyl ether of hydroquinone (which can depigment skin) and phenyl-beta-naphthylamine are the most common sensitizers. The accelerators, mercaptobenzothiazole, tetramethyl thiuram monosulfide and diphenyguanidine, and the peptizer, thio-beta napthal, are the chemicals causing most of the dermatitides attributable to rubber. Two other accelerators, disulfuram (Antabuse) and thiuram, will produce itching, redness and hives in those exposed who ingest alcohol. Thiuram is also used as a lawn fungicide (Tersan). Occasionally bleach will activate a rubber accelerator, zinc dibenzyl dithiocarbamated (ZDC) to become highly allergenic.

Elastic in hair nets may cause dermatitis, and ribbons or wrap-around hair nets may have to be substituted. Where an eruption is due to a rubber condom, Fourex (Schmidt) fish-skins can be substituted.

Adhesive tape can cause a miliaria-like occlusion of poral openings, although true contact dermatitis spreads beyond the margin of the contact with the tape.

Latex cements are used in the shoe and textile trade. Vulcanizing solutions come in two solutions which, when mixed, seal punctures. It takes a few hours to cure, and sensitization can occur from the various chemicals. Non-vulcanizing rubber solutions are used in the shoe industry and automobile trimmings and can cause dermatitis.

Non-rubber Adhesives. These are chiefly synthetic resin adhesives which can sensitize, although fish glues generally do not. Glues made from cotton (e.g., cellulose acetate) are not sensitizers, and neither is collodion. Vegetable gums such as karaya, acacia and tagacanth are sensitizers.

Contact Dermatitis to Soaps and Detergents Dishwashers, housewives, laundresses and surgeons, often show dehydration or shriveling of the keratin layers, which leads to irritation (primary irritant type dermatitis). Coconut-oil-containing soap is often the worst culprit. Neutral soaps, such as Cetaphil, Lowila, Basis, Oilatum, or Dove are much less drying. Many of the stronger antibacterial soaps, such as Dial, Zest, Lifebuoy, Safeguard and Palmolive Gold, are sensitizing as well as drying, and may be photosensitizing.

Contact with clothing washed in strong soaps or detergents (for instance sheets used by bed patients) can lead to dermatitis. This is especially true if bleach or whitener is used. The laundry detergents most likely to cause a reaction include Axion, Bold, Ajax Detergent, Cold Power, Salveo Tabs, Coldwater All, Amway, Arm & Hammer, Era and Dynamo.

Contact Dermatitis to Deodorants and Antiperspirants These products often contain neomycin, zirconium, formaldehyde and antibacterial agents, such as hexa chlorophene, which can sensitize, as well as aluminum salts. Deodorant soaps containing salicylanilide derivatives or hexachlorophene analogs can photosensitize. (Examples include Dial, Zest, Lifebuoy, Safeguard, Palmolive Gold, Irish Spring, or Coast).

Contact Dermatitis from Clothing Natural fiber clothing, made from wool, cotton, linen and mohair, have never in themselves been shown to be sensitizers. Sizing and stiffening cotton with starch orrosin may produce dermatitis.

Dermatitis may occur more frequently from the use of dark clothing. Heavy perspiration, especially in oily-skinned individuals, causes more bleeding of the dye (e.g., widow's dermatitis).

Fabric finishes which are used to increase durability, to soften of stiffen a fabric, or to impart waterproofing, crease resistance or other properties to the fabric. The use of formaldehyde or its resins in clothing is widespread, but the incidence of resulting dermatitis is comparatively low. These are used to make fabrics crease resistant, water-repellent and shrink resistant. Dermatitis occurs mostly in obese women who demonstrate a dermatitis starting in the axilla and later affecting the sides of the neck, the antecubitals and the inguinals. In men, it is usually in the inner thighs, gluteal folds and back of the knees.

Stoddard solvent or other dry-cleaning solutions will occasionally produce a clothing-oriented dermatitis, as will moth crystals. Airing the clothes for a few days before wearing them will usually prevent this.

Management of clothing dermatitis involves the use of Decadron spray, which contains isopropyl myristate, a film or "spray-on-shield" which suppresses sweat and may protect the fabric and acts as a deodorant. Weight loss in obese women sometimes seems to help, as well as avoidance of panty girdles. Those who are sensitive to formaldehyde must avoid wash-and-dry or wash-and-wear and drip-dry clothing.

Contact Dermatitis in Footwear the chief cause here is the thermoplastic or rubber-boxed toes, and the cements and dichromates used in tanning. Dyes, anti-mildew agents, formaldehyde and nickel eyelets or nickel in arch supports also can cause dermatitis. A waterproofing silicone spray externally applied to the shoe can also be the cause. The dermatitis usually begins on the big toe and spreads to the rest of the foot. Socks washed in Bold or bleached with a strong whitener can also cause dermatitis.

Formaldehyde is used in the tanning of white leather shoes in "elk," "white kid" and "new bucks." Tannins obtained from trees are used to tan leather (vegetable tanning) and do not cause dermatitis. However, if the shoe is made of vegetable-tanned leather, the lining should not be chrome- tanned.

Sweat leaches out chromates from the leather, so controlling perspiration is essential. Zeasorb Powder (Stiefel) and Dr. Scholl's foot granules in soap are excellent for reducing some of this.

Diaper dermatitis, better known as diaper rash, is a sore, red rash that appears on skin that is covered by a diaper. A type of irritant contact dermatitis, diaper rashes are usually caused by prolonged contact with moisture. In addition, the bacteria found in bowel movements react with chemicals in urine and creates a build up of ammonia and other chemicals that irritate the skin. There is no apparent link between diaper rash and cloth or disposable diapers.

The best treatment for diaper rash is to keep the area as clean and dry as possible. This requires frequent diaper changes. Gently cleanse the skin after a bowel movement with a mild soap, rinse with warm water, and then dry the skin completely. If the skin is cracked, you can apply a barrier cream to protect the skin from moisture. It’s recommended that you let the child’s skin get as much air as possible. You can do this by letting the child nap without a diaper, placing a waterproof pad or open diaper under his or her bottom to protect the bed from urine or bowel movements while the child is sleeping. If you use cloth diapers, avoid plastic pants, which do not allow airflow. It’s a good idea to use disposable diapers at night because they pull the moisture away from the child’s skin. With treatment, diaper rashes should begin to heal within three days. Because a baby has a large ratio of skin to body weight, it is best to avoid steroid creams, which are absorbed into the bloodstream through the skin. Only use a steroid cream if recommended by your doctor for severe cases of diaper rash. A yeast infection is treated with a special antifungal cream.

You can prevent diaper rash by changing diapers frequently so the skin stays dry. Applying a light layer of cornstarch may help to prevent diaper rash. Talcum powder should not be used because it can be inhaled and cause respiratory infections. If you wash your own cloth diapers, be sure to use bleach to sterilize the diapers. Contact your doctor if a diaper rash does not improve with treatment after several days.

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.

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.

Irritant contact dermatitis is produced by a substance that has a direct toxic effect on the skin. After exposure to an irritant, a skin reaction can occur immediately or gradually after repeated exposure. Examples of common irritants include acids (certain toilet bowl and drain cleaners, dishwasher detergents), alkalis (ammonia, lye), cement, turpentine, and paint thinners.

Itching and burning are common in both categories of contact dermatitis.

With acute and mild exposure, there is typically redness, swelling, and oozing. If left untreated, the condition can result in dry, thickened, cracked skin.

Irritant contact dermatitis is often more painful than itchy, and is the result of an offending agent that actually damages the skin with which it comes into contact. The longer the skin is in contact—or the more concentrated the agent—the more severe the reaction. Water with added soaps and detergents is the most common cause. Thus, it is not surprising that these reactions appear most often on the hands, and are frequently work-related Individuals with other skin diseases, especially eczema, are most susceptible.

This is generally found in men who clean grease off their hands, using either methylated spirit or a detergent or trichloroethylene parts cleaner, in mechanics who use other strong primary irritant chemicals, and in housewives who use detergents.