Contact Dermatitis or Contact Eczema

Understanding Contact Dermatitis

The word ‘dermatitis’ refers to an inflammation of the skin. Contact dermatitis is the medical term used to refer to an irritation of the skin caused by direct contact with a substance, which is foreign to the body. Some common allergens include cleaning solutions, cosmetic additives, industrial chemicals, perfumes, metals and latex rubber additives. Contact dermatitis is classified into two different types: allergic dermatitis and irritant dermatitis. Included are also a couple of contact dermatitis pictures to help distinguish contact dermatitis from other forms of eczema.

Allergic Contact Dermatitis

The allergic form of contact eczema is the result of the immune system’s response towards a tiny and structurally simple non-protein molecule. Allergic contact dermatitis is due to a cellular immune system response that is initiated by the T-lymphocytes, a blood cell type, which has certain exterior molecules that allows the cell to recognize certain chemical types of allergen. As soon as the lymphocytes are exposed to the allergen, a number of chemicals are triggered and released directly or used as a form of stimuli to other cells, which then results to itchy dermatitis. This type of reaction typically develops within the next 24 and 48 hours from exposure.

Several plants, substances, chemicals and medicines cause allergic contact dermatitis. Among the most typical plants that are known to trigger contact dermatitis are poison ivy and poison oak as well as the poison sumac. The allergenic forms of chemicals known to set off adverse reactions are found in the oils or sap of these plants.

Fragrances in soaps and preservatives and emulsifiers in shampoos, lotions, perfumes and cosmetics can set off allergic reactions that result to contact dermatitis. Substances such as nickel found in jewellery and most belt buckles, some ingredients found in leather-tanning agents, chemical additives found in latex gloves and certain components of hair dyes or straighteners cause allergic reactions. Medications such as Neomycin, Neo-Tab and Mycifradin are also known to be among the common causes of allergic contact dermatitis.

Contact Eczema on Upper Body
Contact dermatitis on upper body

Irritant Contact Dermatitis

The irritant type of contact dermatitis is the result of the skin encountering a substance, which damages or irritates the skin. There is no allergic reaction as the response occurs on the initial exposure. The severity of the reaction is dependent on the period of exposure to the irritant. Chemicals, including solvents and cleaning products, along with strong formulations of household cleaning solutions such as household detergents may also be an underlying culprit of dermatitis.

Diagnosing and treating contact dermatitis is challenging, as distinguishing between them is difficult. A full history and physical examination are required to ensure that the correct treatment is provided.

With irritant contact dermatitis, a red rash is the usual reaction but with allergic contact dermatitis, the rash appears a day or two after the exposure. Small, fluid filled vesicles that weep are characteristics of both types of contact dermatitis. The skin also becomes red and itchy; however, irritant contact dermatitis can be more painful than itchy. Irritant contact dermatitis, mostly affects the hands as they exposed to dipping into washtubs or buckets. A reaction may take up to 4 weeks to resolve completely.

Common Causes of Contact Eczema

  • Poison Ivy. The allergic reaction from poison ivy is characterized by linear streaks of acute dermatitis wherever the plant has been in direct contact with the skin.
  • Nickel. This is the leading cause of allergic contact dermatitis in the world and is increasing in the US whilst decreasing in Europe due to new regulations. In rare cases, nickel in the diet can also cause dyshidrotic eczema.
  • Jewellery and Metal Objects. The dermatitis reaction occurs where jewellery pieces or metal objects like belt buckles containing nickel make contact with the skin.
  • Chemicals. Considered an occupational allergen as workers, e.g. hairdressers, caterers, retail clerks, metalworkers and domestic cleaners are exposed to chemicals, which cause vesicles to develop on the sides of the fingers.
  • Preservatives. Chemicals used as preservatives for cosmetics, moisturizers and topical medications are a major cause of contact dermatitis. Quaternium-15 is the biggest culprit with isothiazolinones (Kathon CG) in close second.
  • Fragrances. Fragrances found in perfumes, colognes, aftershaves, soaps and in other numerous products is another cause of allergic dermatitis. Some unscented products may also contain fragrance chemicals used as a component but not labelled as fragrance. Deodorants are the most common cause of allergic contact dermatitis as it is applied to skin, which is already abraded from shaving, especially in women.
Contact Dermatitis on feet
Contact dermatitis on feet

Contact Dermatitis Treatment

Keep in mind though, that the immune system is like a computer and stores the chemical or other substance, which caused the allergy, and if you do encounter it again, the rash is likely to re-appear.

The best way to prevent contact dermatitis is by avoiding the triggers, and to take all the necessary precautionary steps to protect your skin.

It is imperative to protect yourself if you work with chemicals or at industrial sites or when working outdoors with plants and animals. Wear protect clothing with long sleeves, long pants and gloves to protect against allergens and irritants.

If exposure does occur, then wash the affected area with soap and cool water, which should prevent the rash from developing.

If the dermatitis, allergic or irritant, occurs often, then you may want to see a dermatologist or skin allergy expert.

There are approximately 25 chemicals, which are responsible for more than half of all allergic contact dermatitis, including nickel, preservatives, dyes and fragrances.

The prognosis looks good for contact dermatitis treatment because once the offending substance causing the allergic reaction is removed and exposure is limited or nullified then the rash should disappear in less than 3 weeks. With treatment, the symptoms disappear quicker.

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