Causes of Contact Eczema

The symptoms of almost all the types of eczema cause itching and redness, and some will blister, weep or peel. The degree of severity varies with each individual from a mild form of dry, easily irritated sensitive skin, to a severe form in which the skin is broken, scaly, raw, bleeding and can be prone to recurring infections. Contact eczema is caused by physical contact with an irritant or allergen. Any contact eczema that is NOT ATOPIC ECZEMA has two types – Irritant Contact Eczema and Allergic Contact Eczema.

Contact eczema can be divided into two distinct problems:

  • Direct Irritant Contact Dermatitis: Results from exposure to acids, alkaline mixtures, detergents and various other chemicals that acutely inflame the skin. The condition can become chronic with repeated exposure. This form of eczema is often encountered in the workplace. Direct irritant contact eczema can occur at the first exposure to the irritant. For example, most people will develop eczema on first exposure to strong chemicals that are acid or alkaline in nature.
  • Allergic Contact Dermatitis: Results from exposure to an allergen that sensitizes the skin leading to acute inflammation when re-exposure occurs. Prior exposure to the agent is necessary for allergic contact eczema to occur.

It is easier to find the cause of Irritant Contact Eczema than it is to find the cause of Allergic Contact Eczema. Because there is generally a time lapse between contact of an allergy-causing chemical and the outbreak of the allergic rash, it can be difficult to identify the allergen causing the rash.

There can also be difficulties distinguishing allergic contact eczema (which is an immune response) from irritant eczema (which is a direct skin reaction against an irritant substance). In practice, this difference is not so important because the same lines of treatment are required for both.

In particular, a search needs to be made to try and identify a possible allergen. The most common way to do this is to test a person’s skin against a battery of standard test substances, all of which are known to possibly cause contact allergy. This is called 'patch testing'.

If allergy testing reveals a cause that can be removed, the problem is quite likely to resolve. This is not true for everyone, particularly individuals with hand eczema. It is unclear why this is so. Sensitivity will remain dormant, however, and later exposure will be followed by an eczema reaction.

Moisturizers and steroid creams do work for contact eczema, but the extent of improvement also depends on the degree of sensitization and the level and frequency of exposure to the allergen.

If the offending substance is repeatedly being re-applied to the skin, this can result in using a lot of treatment to little effect.

Occurence of Contact Eczema

One may handle a material (e.g. rubber gloves, jewelry, cement) for many years with no problems and then suddenly break out in a rash. The rash is not necessarily localized, but may be widespread. If the rash improves, when one is away from home than one can suspect the cause is something in the home. If the rash improves when one is away from the place of regular employment, then the cause may be the material handled at work.

Irritant contact eczema is similar to allergic contact eczema and is caused by frequent contact with everyday substances such as detergents in toiletries or cleaning products.

Some of the main differences between an irritant and allergic contact eczema are:

  • An irritant will cause a reaction in everyone who comes in contact with it, while an allergen will trouble only those people with the greatest susceptibility for developing allergic reactions.
  • The skin effect from an irritant will be almost immediate – from stinging or burning to caustic burns. There will be no immediate effect from an allergen. The latter takes time to develop. When it does, itching is a prominent symptom.
  • An irritant contact eczema seldom manifests itself as red vesicles which combine to form moist patches. Allergic contact dermatitis always results in red vesicles that combine to form moist patches.

Allergic Contact Eczema

Allergic contact eczema 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. For some reason, more women than men suffer from allergic contact eczema. A rash may take a week or more appear after the first contact with whatever is acting as the allergen.

Not all individuals are predisposed to suffering from allergies. In the case of allergic contact eczema, only those predisposed to certain allergens (i.e. chemicals, nickel, rubber, plastics, glue, adhesive tapes, certain medications, or plants) will be affected.

To be diagnosed with allergic contact eczema, one must have to have come in contact with the offending allergen previously. The rash first appears only at the site of skin contact with the allergen. Later it often spreads and may involve skin well away from the contact site. This is because the immune cells become activated and migrate out through the bloodstream to other areas of the body. If allergic contact eczema is suspected, it is to remember where it first started when taking the medical history behind the development of a rash.

The cells of the immune system work in various ways in skin disease. The rash that occurs after being stung by nettles happens within minutes of contact. It is due to the release of chemicals such as histamines by immunity cells within the skin layers. This is known as immediate hypersensitivity. This is what happens in irritant contact eczema.

Slower-acting forms of response by the immune system occur because the population of cells that react against the invading substance or organism (allergen) needs to be built up from a small number of 'memory' cells that recognize the allergen. Over two or three days these cells give rise to others that in turn switch on other defense mechanisms such as the release of chemicals that attract the scavenger cells of the immune system. Because of the lag between initial contact and subsequent reaction, this is called delayed hypersensitivity. The skin reactions underlying allergic contact eczema are of this type.

It is not known why some substances are particularly prone to causing contact allergies, but some of the common culprits include:

  • Nickel: a white metal often used in jewelry, belt buckles, jean studs, metal watch straps, and bra fasteners. Many other metals can also cause reactions.
  • Perfumes: Balsam of Peru is a component of fragrances which can cause contact allergies
  • Rubber and Related Chemicals: used in shoes, tires and clothing
  • Potassium Dichromate: used in cement, leather and matches
  • Hairdressing Chemicals (paraphenylenediamine)
  • Medications: used in lanolin, neomycin (antibiotic), fusidic acid (antibiotic), steroid creams and cetearyl alcohol (used in emollient creams)
  • Epoxy Resins: found in glues used in hobbies, woodworking, and glass fiber construction
  • Colophony: a resin from spruce trees, used in sticking plaster adhesive
  • Plants: both by direct contact and by contact with airborne particles

In the food industry a wide variety of foods are known to potentially cause skin reactions. These include**:

  • Sugar
  • Flour/dough
  • Citrus fruits and their peels
  • Other fruits and vegetables
  • Spices, herbs, seasonings (e.g. horseradish, mustard, garlic)
  • Fish and seafood
  • Meat and poultry

**This is by no means a comprehensive list of all possible allergens which can cause allergic contact eczema.

Some of the materials known to potentially cause skin reactions are themselves components of common treatments for eczema (e.g. lanolin in moisturizers and hydrocortisone in steroid creams). Therefore, if the condition is worsening or proving resistant to treatment, it may be that the treatment itself is contributing to the skin problem.

Sometimes the cause and effect relationship is obvious, with a red scaly reaction around an earring or under a watchstrap. At other times, especially if a long time has passed since the initial exposure and sensitization, it may be impossible to distinguish contact allergic from other types of eczema.

Irritant Contact Eczema

Irritating substances which cause a stinging and burning sensation with some itching fall into the category of Irritant Contact Eczema. If such irritants are strong and caustic, such as acids or alkalis, they can produce burns or ulcers upon first contact with the skin. Weaker irritants such as soaps and detergents will make the skin dry, scaly, red and fissured. Chapped red hands are an example of this.

Almost everything we do involves our hands. Identifying and avoidance of the irritant is the first and foremost step in treating irritant contact eczema. Common hand irritations (which may vary from mild to severe) will respond to emollients and in severe cases, one’s doctor may prescribe limited time doses of steroid ointments. An oral antibiotic may have to be taken if the skin becomes infected. Some of the more common irritants are alkali soaps, detergents, shampoos, bubble bath preparations, antiperspirants, depilatories, rubbing (isopropyl) alcohol, permanent wave liquids, household cleaners (such as lye, oven cleaners, toilet bowl cleaners, polishes, bleaches, ammonia), and fruit and vegetable juices.

Irritant contact eczema (or dermatitis) is far more common than allergic contact eczema. It is the second most common cause of occupational-related health issues - the most common being muscle and joint pains and injuries.

Almost all occupations in which skin (usually the hands) is made wet repeatedly are associated with irritant contact eczema. Hairdressers, cleaners, catering workers, food processors, and fish handlers are occupations which require frequent hand washing or contact with water. Prolonged contact with water swells the surface cells of the skin and disrupts the normally tight joins between them, exposing the more vulnerable deeper layers. In metal engineering light machine oils are commonly in contact with the skin, and as many as half of all workers in this industry suffer from irritant contact eczema. Many just accept it as part of the job.

It's not just the industrial environment in which skin-unfriendly agents can be found. Many household items such as cleaning materials, detergents and bleach are potentially just as harmful. Hobby interests can lead to frequent skin contact with adhesives, paint, oils and cement.

Some methods of treating irritant contact eczema include:

  • Ceasing contact with the offending substance would be the ideal, but this is often impractical. In these circumstances, however, the aims of treatment can only be to reduce symptoms. Unfortunately, some irritants cause skin reaction even with very little exposure.
  • Using protective gloves. Since the latex or rubber in gloves can cause or worsen eczema, some people find it helpful to use cotton-lined gloves or separate cotton inner gloves to reduce the degree of direct skin contact.
  • Frequent moisturizing is essential, especially in wet-work jobs. Barrier creams can be of some benefit, but may be counter-productive if they encourage workers to take less care, thinking the barrier cream alone protects them. Anti-inflammatory (steroid) creams are the mainstay of irritant eczema treatment.
  • Applying Eczema-Ltd III patented topical skin conditioner disks to the affected areas.

Employers have a duty to protect their workers against occupational hazard. Similarly, workers have a duty to make use of the protection measures offered by their employer. Larger companies in known high-risk areas of employment will probably make use of an occupational health doctor or nurse who can evaluate the problem and advise on corrective measures. Most workers are not so lucky.

Compensation issues can arise where the employer fails to provide sufficient protective measures or warnings about the possibility of eczema arising. However, proving such cases is a lengthy and expensive process that is not usually successful.

It's much better to be aware of the possibility of a link between skin reactions and your occupation and to take as many practical steps as possible to avoid running into trouble.