Contact eczema (CE)

What is contact eczema?

Allergic contact eczema (CE) is an immunological reaction that occurs when a low molecular weight chemical (hapten) is associated with skin proteins and this causes sensitization with the production of a type of cells (T lymphocytes) that when they react with allergens trigger the release of chemical mediators of pro-inflammatory activity and with them the manifestation of the disease.

The location of the lesions varies according to the area where the allergenic chemical is applied: head and scalp (dyes, shampoos), face (cosmetics, etc.), ears (metals), hands (detergents, metals, etc.).

What causes contact eczema?

There are a very large number of chemicals capable of causing contact eczema (CE) and new ones are described every year. Many of them are of industrial origin and their exposure is occupational and may constitute an occupational disease.

The main agents of contact eczema (CE) include metals (nickel, cobalt, chromium), rubber compounds and resins, para-aminobenzoic group, topical drugs, cosmetics, perfumes and preservatives.

How is contact eczema diagnosed?

The clinical history, as in other cases, is essential and should be directed to know aspects related to occupation and hobbies, form of onset of the reaction, localization.

The most effective and practical method of diagnosis is the performance of epicutaneous tests, also called "patch tests" in which the products to be studied, duly prepared in glycerin, are applied in small quantities on the skin and in an occlusive manner for 48 hours. After that time and up to 96 hours, readings are taken in search of an inflammatory reaction that can range from a simple redness to the production of blisters. The interpretation of these tests must be careful and always relate them to the clinical history. There are some varieties that require the application of light or UVA rays.

What is the treatment of contact eczema?

In the acute phase with exudative lesions, compresses with antiseptics and astringent products are applied. When lesions improve, topical corticosteroids are used.

In very severe cases, short courses of oral corticosteroids are administered.

In the chronic phase, emollients and topical corticosteroids as well as antihistamines are used to prevent itching and scratching.

The only treatment for allergic contact eczema is to eliminate contact with the product(s) causing the allergy. This can lead to occupational problems in occupational contact eczema (CE).