Contact allergy: causes and treatment
About 10 to 20 percent of the population in Germany are affected by a contact allergy. When the skin comes into contact with an allergen, painful rashes form. But what exactly can trigger a contact allergy and what can you do about it? Here we have collected the most important information.
What is a contact allergy?
A contact allergy is an allergic reaction of the skin to contact with certain substances. The allergy usually occurs about 24 to 72 hours after contact with the allergen (delayed type) and affects the skin areas where the contact took place.
The contact allergy is caused by a “misdirected” immune reaction of the body. In a first phase, the so-called sensitization phase, the body begins to form defense cells against the respective contact allergen. The cause of this immune reaction has not been clearly clarified. Since no skin reactions occur during this time, the sensitization phase usually goes unnoticed.
The so-called trigger phase begins when you come into contact with the allergen again. The previously formed antibodies are directed against specific components of the allergen and trigger unpleasant skin reactions.
How does a contact allergy manifest itself?
The most common symptoms of a contact allergy are itching, (oozing) redness, swelling, blistering or nodule formation and scaling of the affected skin areas. Since the inflamed areas are a good breeding ground for fungi and bacteria, skin infections are not uncommon as secondary diseases.
If the allergen is not avoided, so that the skin keeps coming into contact with it, the symptoms of contact allergy can develop chronically and lead to a coarsening of the skin in the affected areas and to increased horn formation.
What can cause a contact allergy?
In principle, any substance can trigger a contact allergy – regardless of whether it is natural or artificial. For example, plant ingredients, metals or chemicals can trigger allergies. Some substances are particularly common as allergy triggers:
- Fragrances in cosmetics or care products
- Nickel (e.g. in costume jewelry or jeans buttons)
- latex
- hair dye
- preservatives and colourings
- cleaning supplies
- Plant components (e.g. from marigolds, arnica)
How is a contact allergy diagnosed?
Since the symptoms of a contact allergy can be very similar to those of other common skin diseases, such as neurodermatitis, and usually appear with a delay, it is usually difficult to identify a suspected contact allergy yourself. A test under medical supervision is therefore highly recommended in order to be able to clearly identify the allergy-causing substance.
In a preliminary discussion, the attending physician narrows down the possible allergens by asking questions about the patient’s habits and taking into account their own observations of allergic symptoms. An allergy diary can also be helpful in this regard, in which it is recorded when allergic reactions occurred, how severe they were and what a potential trigger could have been.
In the so-called patch test, also known as a patch test, certain allergens are then applied in small doses to the skin on the back using special patches. After 48 hours, the patches are removed and the doctor assesses the skin reactions. In most cases, further examinations of the skin take place in the following days in order to record reactions that occur later.
How is a contact allergy treated?
Once a contact allergy has developed, it will remain for life. Hyposensitization, as in the case of immediate-type allergies, is not possible. The only way to live symptom-free is therefore a complete allergen avoidance. This means that contact with the allergenic substance is completely avoided. An accurate diagnosis is therefore of great importance.
In severe cases, in which the contact allergen cannot be sufficiently avoided for professional reasons, a contact allergy can lead to disability. This is the case, for example, with hairdressers or cleaning staff, who come into contact with the allergenic substances every day.
For the treatment of acute eczema, ointments are usually prescribed that have a slight anti-inflammatory and pain-relieving effect. If the itching is severe, a remedy can also be prescribed that results in a light local anesthetic. In particularly severe cases, treatment with ointments or creams containing cortisone can also be considered.
In order to support the skin’s natural protective function, it is advisable to only use skin care products with a pH value between 5 and 6.5. In addition, moisturizing creams, for example with urea, should be used regularly to strengthen the skin’s protective acid layer.