Brief Answer:
allergic, inflammatory, autoimmune, idiopathic (cause is not known)

Detailed Answer:
HI, thanks for using healthcare magic

The skin is made up of the epidermis (the outer layer) and the dermis (under the epidermis).
Eczema involves changes or damage to the epidermis which can result in itching, redness, dryness, flaking, infection (as a result of the itching), blistering and cracking.

Not all of these may be present.

It can be due to allergic reactions, autoimmune causes (essentially body reacting to a part of itself), inflammatory or idiopathic (cause is not known).

There are different types but the most common is atopic eczema which can be associated with food allergy, asthma or/and sinusitis or rhinitis.
Atopic eczema is a pruritic disease (itchy) of unknown cause that causes itching, rash, dry skin and thickening of the skin.
The theory is there is abnormal function of the immune system leading to it having increased sensitivity.

The other types are : (1)allergic contact dermatitis (contact of the skin with a particular agent causes an allergic reaction eg chain around neck

(2)dyshidrotic eczema

(3)asteatotic eczema-occurs when excess water is loss from the skin, more common in older persons

(4)nummular eczema- exact cause unknown but considered to be an adult onset form of atopic dermatitis

(5)seborrheic dermatitis - abnormal response of the skin on the scalp, face and upper trunk. Associated with the presence of a particular fungus

(6)stasis dermatitis- occurs in the legs in persons with a history of venous disease

(7)irritant contact dermatitis- due to a response of the skin to direct chemical damage eg with soaps or detergents

I hope this helps,feel free to ask any other questions

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