Contact eczema

Contact eczemas always only occur on the area of skin that had contact with the harmful substance. Depending on the characteristics of the contact eczema, redness, swelling (oedema), blisters, scaly skin, nodules or crusts are the predominant feature. With acute eczemas, blisters and weeping forms will frequently predominate. Chronic eczemas therefore tend to be characterised by redness, scaly skin and a thickening of the skin with coarsened, extensive skin lines (lichenification). Eczemas, in particular when they are allergic, are frequently accompanied by very severe itching.

Allergic contact eczema

Contact allergies appear on the skin as highly itchy eczemas. At the beginning, redness and swelling appear on the area of the skin that has been in contact with the allergen; the swelling and redness may 'spread' beyond the area of contact. Itching is also possible, and with severe reactions, blisters can form. The skin weeps when these burst. In the healing-up phase, crusts then form and scaly skin results. If the triggering allergen is not recognised and removed, a chronic contact eczema can form. The skin then becomes thicker and scaly. The skin lines become coarser (skin lichenification).

Irritative contact eczema

An irritative contact eczema develops either after permanent contact with mild irritants (e.g. cleaning agents) or after brief contact with strong irritants (e.g. acid). Mild irritants initially result in dry, chapped skin. Over time, inflammatory symptoms such as redness, itching, and swelling of the skin develop. The skin barrier is damaged and allergens can penetrate more easily. An allergic contact dermatitis can also develop. Sore, weeping areas develop as the disease progresses.
Strong irritants result directly in burning, stinging and/or itching of the skin and redness, swelling and the formation of blisters. When the blisters burst, crusts form and later scaly skin.