It is difficult to determine the exact cause of eczema as there are many different types of eczema and each has its own causes. Largely, the cause of atopic (endogenous) eczema is genetic (inherited). Atopy usually runs in the family and there is a family history of one or more disorders like asthma, hay fever, urticaria, food allergies, etc. A person who has atopic eczema is more likely to develop allergic reactions to many other things as well.. The causes of certain types of eczema remain to be explained, though links with environmental factors and stress are being explored.




There are many causes for exogenous eczema and following are the few common ones:

::Contact with irritants such as detergents, soaps, certain clothings or shoes, metal compounds (nickel, mercury, etc), dyes, cosmetic preparations (deodorants, nail paints, etc), topical creams, rubber, leather, resins, etc.
::Exposure to sunlight.
::Napkin rash in infants.

For certain other types of eczema, such as infantile and adult seborrhoiec eczema, discoid eczema, the causes remain unknown.

In the later years eczema can be caused by a blood circulatory problems in the legs (stasis dermatitis).