Skin
Pathological changes to the skin have many different causes. Predisposition, immune reactions and environmental factors also play a role.
![Mother holds her infant, who suffers from severe neurodermatitis, in her arms and supports his head with her hand.](/userfiles/images/haut/neurodermitis/aha-atopic-dermatitis-eczema-neurodermatitis.jpg)
Atopic dermatitis (atopic eczema, neurodermatitis)
Atopic dermatitis/eczema or neurodermatitis is a chronic skin disease that typically first manifests in infancy.
![Picture detail: Well-groomed woman's hands; a bracelet. The woman is playing with it.](/userfiles/images/haut/kontaktekzem/aha-contact-dermatitis.jpg)
Contact dermatitis
Contact dermatitis – also known as contact eczema – is an inflammatory non-infectious reaction of the skin to external substances and influences.
![Hand with typical reddish pustules of urticaria.](/userfiles/images/haut/urtikaria/aha-urticaria-hives-nettle-rash.jpg)
Urticaria (hives/nettle rash)
In urticaria, also known as hives or nettle rash, itchy wheals form on the skin as on contact with stinging nettles.
![Common in the occurrence of angioedema are swollen lips, shown here in a man.](/userfiles/images/haut/angiooedem/aha-angioedema-en.jpg)
Angioedema
Severe local swelling of the skin might indicate a case of angioedema. The condition mainly affects the arms and legs but can also affect the face and the genital area.
![Certain occupational groups have a greater risk of hand eczema - including hairdressers. Picture detail: At the hairdresser's, cutting hair.](/userfiles/images/haut/chronisches-handekzem/aha-chronic-hand-eczema.jpg)
Chronic hand eczema
Substances that are harmful to the skin, irritants, allergy-causing substances but also hereditary factors can be a reason for eczema of the hands. The symptoms differ greatly and vary in severity.
![A mother puts cream on her toddler's face.](/userfiles/images/haut/sonnenallergie/aha-sun-allergy.jpg)
Sun allergy
One day in the sun and the skin turns red, itches and develops a rash - despite the use of sun cream. What is happening? Could it be a sun allergy?
![Elbows and undersides of two arms badly affected by psoriasis](/userfiles/images/haut/psoriasis/aha-psoriasis.jpg)
Psoriasis
Psoriasis is a chronic, non-contagious disease that primarily affects the skin.
![Naked shoulder area of a woman with the white patches on the skin typical of vitiligo.](/userfiles/images/haut/vitiligo/aha-vitiligo.jpg)
Vitiligo
Vitiligo is a chronic disease characterised by patchy discolouration of the skin.