Triggers A Contact Allergy

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Triggers A Contact Allergy
Triggers A Contact Allergy

Video: Triggers A Contact Allergy

Video: Triggers A Contact Allergy
Video: Contact Dermatitis 2023, September

Contact allergy: triggers & prevention

There are many possible triggers for a contact allergy. The skin becomes red and itchy where there was direct contact with the triggering substance. Metals (e.g. nickel) most frequently trigger allergic contact eczema.

One can also be exposed to allergenic substances in the professional area. You can also find out what preventive measures are available.


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  • more on the subject
  • Advice, downloads & tools
  • What is allergic contact eczema?
  • How does allergic contact eczema come about?
  • What are the causes of a contact allergy?
  • How can you prevent a contact allergy?
  • Hand care tips
  • What is irritant contact eczema?

What is allergic contact eczema?

With a contact allergy, the so-called allergic contact eczema occurs. The skin becomes red and itchy where there was direct contact with the triggering substance. Contact allergy is an allergy of the so-called late type. It takes some time for the allergic reaction to occur. Allergic contact eczema occurs primarily in the armpits, hands, face, hips, buttocks, genitals, legs and feet. However, eczema is not only found on the skin where there was contact with the allergen. This skin condition rarely spreads to other areas and can even spread to the whole body. Sometimes skin symptoms appear that do not look like eczema - especially on mucous membranes such as the oral mucosa. There, a contact allergy manifests itself primarily as a poorly healing wound - which can also spread around the mouth or to the lips (allergic contact stomatitis).

How does allergic contact eczema come about?

Visible skin irritation occurs approximately 48 to 72 hours after contact with the allergen. You can find out more about the different allergy types under Allergy: What is it? Contact allergies or allergic contact eczema develop due to a reaction of the T lymphocytes. These have already been sensitized to an allergen - an allergy-causing substance - that is linked to the body's own proteins. If the contact with the allergenic substance occurs for the second time, allergic contact eczema occurs.

However, there is also a rare contact dermatitis of the so-called immediate type. Urticaria and dermatitis occur at the point of allergen contact immediately after contact (in less than thirty minutes). These actually belong to another form of allergy that is usually responsible for hay fever, asthma, food allergy, and insect venom allergy. This occurs especially with latex, cat and dog hair, roots and vegetables.

If the skin is dry or inflamed, it is easier for the allergen to penetrate. Likewise if you sweat or wear tight clothing. Research assumes that a genetic tendency is also a risk factor for the development of contact allergies. Atopics are also more at risk of sensitizing themselves to a contact allergen.

What are the causes of a contact allergy?

A total of over 3,000 contact allergens are known. A few hundred of these often cause allergies. The most common include:

  • Nickel sulphate - "nickel allergy" (eg contained in metal alloys such as jewelry or in some cooking pots),
  • Fragrance mixes (mixtures of fragrances e.g. in cosmetics, skin care products),
  • essential oils,
  • Cobalt chloride (e.g. in cement, mineral oil products),
  • Potassium dichromate (e.g. in tanned leather or cement),
  • Formaldehyde (preservative and disinfectant),
  • Isothiazolines (preservatives, for example in cosmetics or cleaning agents). The related methylisothiazonlinone is banned in some products in the European Union,
  • Rosin (resin, e.g. in plasters),
  • Propolis (bee resin),
  • Paraphenylenediamine - PDD (e.g. in hair dye or gum),
  • Medicines that are applied to the skin, especially antibiotics,
  • Bronopol (preservative, e.g. in cleaning agents),
  • Plants (e.g. arnica, tea tree oil, propolis, Peru balsam, yarrow) as well
  • Tattoo inks

Most often, nickel and cobalt salts as well as chromium trigger contact allergies. Not only jewelry can contain nickel, but also buttons, glasses, food (e.g. chocolate) and saucepans. But fragrances (e.g. in cosmetics) and chemicals in cleaning agents, hair dyes or clothing often trigger allergies. There are also cross-allergies with other substances. If a so-called coupling allergy occurs, two different substances cause a skin reaction at the same time (e.g. with certain creams).

There is an obligation to label a few fragrances that can trigger allergies (INCI list) as well as a regulation for the maximum content of nickel in costume jewelery (European Chemicals Regulation - REACH). You can find more information on fragrance labels on the AGES website; more information on nickel can be found in the legal provisions of the Nickel Ordinance.

Allergic contact eczema rarely arises from the ingestion of foods containing nickel (e.g. chocolate, soy or other legumes, black tea) or from airborne transmission (e.g. from chemicals such as epoxy resins).

Profession as a risk

Occupational contact with allergenic substances increases the risk of developing an allergy. However, it can take months or years for this to show up. Further information (including questions about insurance law) about occupational diseases can be found on the AUVA website at

How can you prevent a contact allergy?

In addition to avoiding the triggering substance, it is recommended to use gentle skin cleansing agents with a pH value between six and 6.5 and dry yourself well after washing as a prevention and accompanying therapy for contact allergy. In addition, cosmetics without fragrances and preservatives prove to be helpful.

Natural cosmetics, which are often touted as "purely natural", often contain highly allergenic substances, such as Peru balsam. Before putting on clothes for the first time or using new bedding, wash them to remove any residue from textile manufacturing. The correct use of sunscreen can also help prevent or prevent a contact allergy. Your pharmacist or dermatologist will advise you on suitable preparations.

Hand care tips

Hands are particularly often exposed to substances, for example when cleaning hands or cleaning. If eczema occurs on the hands, practical tips help to prevent it or - in addition to the respective treatment - to alleviate it. These include, for example:

  • Wash hands with soap-free cleaning substances - ensure that they are dried well, including between the fingers.
  • Apply an ointment / cream recommended by your doctor several times a day to your hands.
  • Wear protective gloves when handling cleaning agents or polishes.
  • Always wear gloves in cold weather.
  • If rings are worn, clean them regularly - as well as the skin under the rings.

What is irritant contact eczema?

A distinction must be made between allergic contact eczema and so-called irritative contact eczema, which is not an allergy but rather a skin irritation. In this case, the allergy tests are also negative, but the appearance is similar. The rash appears minutes to hours after contact. It manifests itself less by itching than by pain and is sharply delimited. It can also become chronic (chronic irritative skin reaction) and then flake, and the skin also thickens. The hands, eyelids and the area around the mouth in particular can be affected.

Irritant contact eczema is caused by direct damage to the skin by substances or factors that are irritative-toxic. These can include, for example:

  • Cleaning supplies,
  • Disinfectants,
  • Hair dye,
  • Food (skin contact with raw fish, meat, fruit, vegetables),
  • Heat, cold (e.g. also with water),
  • Plants,
  • Jellyfish, caterpillar hairs (e.g. from the oak processionary moth),
  • Cement dust, wood dust etc.,
  • mechanical loads as well
  • Glass wool.