What is the contact dermatitis?

Contact dermatitis is caused by an allergen capable of triggering an immune response to a specific group of cells, T lymphocytes from memory. These cells, in previous contacts with the allergenicity, were sensitized to this allergen and react each time that there is a new contact.

Characteristics of contact dermatitis

The cutaneous reaction appears 1 to 3 days after contact of the skin with these allergens and are usually characterized by redness, inflammation, vesiculação with exudation and itching at the site. This reaction persists 7 or more days. If this contact is chronic, i.e., repetitive during long periods of time, the skin becomes dry, broken, scaly and hardened.

Although initially the contact eczema appear only at the site of contact, then you can extend to other parts of the body. These characteristics are typical of contact eczema, however there is no contact dermatitis eczematous, as for example: only redness with ardour, hardened skin only, only dryness, pigmented skin, etc. The severity of dermatitis depends on the intensity of exposure and the degree of awareness.

What are the main allergenic substances?

Let us begin by metals

  • Nickel is a very common allergen that is present in many ornaments and accessories shop metal (ex: earrings, buckles), personal objects of metal (ex: sunglasses, watches, coins (1 and 2 euros), objects of secretariat (ex: clips, staplers), kitchen utensils (ex: knives), material (ex: THIMBLE), metal handles of doors or appliances, osteosynthesis material, springs of textile products;
  • The Chromium - is in various materials, namely: cements, metallic materials chromates, some textile dyes, preservatives, material used in the tanning of the leather, photographic supplies, tattoo, pigment to shadows of beauty, waxes of pavement, etc.;
  • The Cobalt is another metal that causes allergy and which can be found in the following materials: paint (blue color) for glass, porcelain, ceramics, paper, textiles, cheek in paints, cement; leather; drying of paints and varnishes, fluorescent paintings, metal alloys (ex: dental alloy, nickel-plated objects, objects with bathroom (metal zippers, buttons, coins) feed for animals, lube oils, powder for welding, wood preservatives, varnishes for tarpaulins, material of photography.


Keep in mind that, contrary to what may seem, cosmetics may contain many elements allergens.

You should have a special care with the dyed hair, the shadows for eyes, mascara, lipstick, nail varnish, skin masks, the sunscreens and perfumes.

The constituents that commonly cause allergies in cosmetics are the perfumes, the parafenilenodiamina, preservatives (euxyl k 400, kathon) and the excipients (lanolin alcohols).

  • Perfumes are the main cause of allergies to cosmetics. Almost all products that are applied on the skin scented ingredients: perfumes, cosmetics, free (ex: soaps, bath gel, aftershaves and deodorants.
  • Parafenilenodiamina is a frequent constituent of paints capillaries. This allergen can also be part of other materials: paints of clothing and footwear, gasoline, oils, masses of lubrication, black rubber, cosmetics like mascara, material of photography.
  • Euxil K 400 is a mixture of 1.2-dibromo-2,4-dicianobutane and 2-phenoxyethanol. These products are used as preservatives, bactericides or fixantes in cosmetics and other products, such as: liquids used in the metallurgical industry, adhesives, paints and emulsions latex paints, dyes, detergents, perfumes, repellent for insects, topical antiseptics.
  • Kathon CG is used as a preservative in the following products: shampoo and hair conditioners, balls of oil or gel to the bathroom, gels for the body and hair care, skin lotions and creams, masks to the skin, oils, soaps, wet cleaning wipes, latex emulsion, liquid cooling system, in the manufacture of paper, fuel for jet engines, radiography, printing inks, detergents.
  • Quaternium is a preservative used in some pharmaceuticals, cosmetics and industrial: creams of the hands and face and other beauty products and skin care, hair lotions, shampoos and soaps, topical medications, paints for rubber, polishes and paints of water, liquids used in the industries of metal like for example liquids to cut.
  • Balsam of Peru consists in esters of acids cinnamic and benzoic, vanillin and styracina and exists in several products: cosmetics and perfumes (used as a fixative and aroma), topical medications, suppositories, pads and syrups for cough, dental materials, flavored tobacco, some food (chocolate, orange, lemon, vanilla, cinnamon and some spices, chewing gum, used as a flavoring agent in drinks, cakes, wines, liqueurs).
  • The PARABENS are used as preservatives in some medications (avoid topical creams and ointments, nasal drops, eye drops, syrups which have the composition parabens, nipagin, nipasol), in some cosmetics (moisturizing creams, Creams lightener, etc) and in some foods (salad dressings, sauces with spices, mayonnaise, mustard, cream derived from milk, dried foods).
  • Other: a few pencil and masks for the eyes can be salts of cobalt and chromium oxide. There are no national market hypoallergenic beauty products.

The rubbers

  • Carbas, mercapto and thiuram are chemical substances that may be part of rubber products: gloves, shoes, elastic, finger cots, underwear with elastic rubber (Bras), toys, diving suits and swimwear, sponges, condoms and diaphragms, adhesives, medical equipment, electric wires, equipment of hemodialysis. They are also used as: plant fungicides used in agriculture, Germicides disinfectants in seeds and grains, bacteriostatic soap, antifreeze mixtures (used as an anticorrosive), soluble oils for carving, greases and lubricants in photography as a emulsifier, sprays and post anti tick and anti fleas used in veterinary medicine, discouraging the consumption of alcohol (thiuram).
  • N-isopropyl-N'phenyl-parafenilenodiamina is a chemical substance used as anti degrading of natural rubber and synthetic, giving him a black coloration. It can be found in tires, shoes and boots, diving suits and swimwear, materials used in civil construction, materials used in the manufacture of doors, windows and staves, materials used in the manufacture of cars, piping some milking machines.

The clothing industry

  • In addition to the metal accessories or rubber (described above), the dyes used in dyeing of fabrics can also cause allergies, mainly dark colors. When the dyes are poorly fixed are easily released during washing or when there is intense sweating (Summer).

The footwear

  • The resin butilfenolformaldeído* is part of the constitution of glues used not only in the footwear industry, but also in carpets, automotive industry, orthopaedic prostheses, leather accessories (belts watches, gloves), in adhesives for domestic use of wood, plywood and insulation material. It can be also found in oils for engines, disinfectants, deodorants, photographic material of revelation and inks
  • Formaldehyde is a volatile gas, irritating or alergizante difficult eviction, which exists in various products and is used in several industries: cosmetic products (used as a preservative and disinfectant), deodorants, shampoos, nail varnish, adhesives (phenolic urea), insecticides, fungicides, bactericides, glues and varnishes, materials of tanning, disinfectants, Cleaning products, cleaning products cleaning, production of mineral wool, fertilizers, materials of embalming, composed of wood, materials used in insulation, plastic dental material, Photography (paper and fluids), paints, printing inks, paper industry, textile industry (used in finishing, hardening, coating), Footwear industry (resin adhesive of urea, urea, urea phenolic plastic), clothing ( friction), resins and plastic materials, calicidas and Antiseptics; used in the production of urea, melamine phenolic resins and acetale; used in histology.


Faced with such a large amount of elements allergens seems an almost impossible task to avoid materials that contain this or these elements. However, the most effective therapeutic measure is prevention, that is, avoiding as far as possible the materials containing the allergens causing.

Many of the allergens mentioned above are used by the textile industry, especially, the latex (rubber), the level, the formaldehyde, the p-phenylenediamine or para-Phenylenediamine, nylon, etc.

Skintoskin products are free of allergenic substances and their raw materials are certified by oeko-tex class 1.

See here the datasheets of our produtos para eczema

Given its importance in the guarantee of security associated with the textile products, our next publication will discuss the various levels of certification OEKO-tex.

In all our communications warned to the fact that the information and advice available on our Blog do not override the opinion/opinion from your doctor and/or pharmacist.

Source: Portuguese Society of Allergology and Clinical Immunology