Allergic contact dermatitis

Contact allergies cause eczema (dermatitis). The typical symptoms include:

• swelling,
• itching, and
• dry skin.

On light skin, you can usually see a reddish rash – often without clearly defined edges. On dark skin, the affected area tends to be dark purple to dark gray in color. It is also typical for small bumps (papules) to develop on dark skin. The skin in that area usually becomes thicker and rougher, too.

In severe allergic reactions, the skin may hurt and feel tight. Blisters might form as well. If the blisters burst, the skin “weeps” (oozes a fluid), scabs form and then flake off.

At first, the symptoms affect only the area of the body that comes into contact with the trigger. This is often the hands, particularly the fingers and backs of the hands. Other areas that are often affected include the face (especially the eyelids and lips), the neck, lower legs and feet. The severity of the allergic skin reaction will mainly depend on which substance the skin came into contact with, and for how long.

In contact allergies, allergic reactions can also later occur in other parts of the body that didn’t come into contact with the substance that triggered the allergy.

Substances that commonly trigger contact allergies include the following:

• Metals (e.g. nickel and cobalt)
• Latex rubber
• Adhesives (e.g. the sticky substances in plasters)
• Plants (e.g. chamomile and arnica)
• Scents (in cosmetics such as lipsticks, perfumes and soaps)
• Cleaning agents and solvents
• Essential oils
• Medications that are applied to the skin

The body already makes antibodies to fight the trigger (allergen) the first time it comes into contact with it. This makes the skin react more sensitively to the substance when it comes into contact with it again. Noticeable symptoms only start appearing over time, after repeated contact with the substance. For instance, hairdressers may develop contact allergies to substances that they touch every day, such as hair dyes or perm solutions. Some people are generally more prone to allergies. They may develop contact allergies in a shorter amount of time.

About 8% of all adults have a contact allergy. They are more common in women than in men. Contact allergies are responsible for 10% of all occupational (work-related) diseases. They commonly affect hairdressers, beauticians, nursing staff, bakers, office workers, metalworkers and bricklayers.

Contact allergies usually first arise in adulthood. The symptoms often go away if they are treated and the triggers are avoided. But contact allergies might also develop into chronic contact dermatitis. The skin then becomes thick and hard, with painful cracks.

It isn’t possible to determine whether or not someone has a contact allergy based on the symptoms alone. But allergic rashes are often a bit different from rashes that are caused by other things. For instance, a rash without clearly defined edges is more likely to be a sign of an allergic reaction. And allergic rashes often occur on various parts of the body.

The doctor will ask you which substances you came into contact with in the days before the symptoms appeared, and whether you have been repeatedly exposed to certain substances in the past.

A patch test can be done to find out whether it is actually an allergic reaction. This involves placing the substances on your skin with the help of patches that are stuck on your back for one to two days. If a rash appears where a patch was, you're probably allergic to that substance. On light skin, the rash can usually be seen as a red area. On dark skin, it is more likely to be darker, and the skin may be bumpy or thicker, which the doctor can feel. It can be easier to see smaller bumps if the doctor shines a light on the area from the side.

Patch tests may actually lead to the development of contact allergies, though. So it’s all the more important that the doctor is well informed about contact allergies and is careful when choosing which substances to use in the test.

Allergic skin reactions are usually treated with steroid creams, ointments or solutions.

But the main thing to do is avoid contact with the substance that triggers the reaction. For instance, if you're allergic to nickel you should make sure that jewelry, buttons or belts that touch your skin don't have nickel in them.

If you can't avoid contact with the substance at your workplace, things like gloves or protective clothing can help. You may also have to switch to other activities at work. If you're believed to have a work-related contact allergy, it’s a good idea to have your dermatologist or company doctor inform your employer’s liability insurance. The insurance will cover certain costs, like the costs of protective measures, if the allergy is recognized as being work-related.

When people are ill or need medical advice, they usually go to see their family doctor first. Information about health care in Germany can help you to navigate the German health care system and find a suitable doctor. You can use this list of questions to prepare for your appointment.