Definition of Eczema
:It is an inflammatory response of the skin characterized in its acute stage by oozing and its chronic stage by lichenification
Types of Eczema
(1)
Contact dermatitis
:Eczema at the site of contact with an exogenous antigen w may be irritant or allergic
-Irritant contact dermatitis non allergic
Strong irritant: e.g. acid,alkaliand coc. chemicals will lead to acute irritant dermatitis up to formation of bullae by single exposure in any exposed individual
weak irritant e.g detergant which which will lead to acute or chronic or cumulative irritant contact dermayiyis
allergic contact dermatitis
exposure to allergens which are normally harmless agents but produce in apredisposed subject atype of alleergy or type IV allergy
The most common allergens are:
nickel, cosmetic chemicals,rubber chemicals, topical agents, local anaesthetics,local antihistaminics, formaldehyde
(2) Atopic dermatitis :
It is the most characteristic type of eczema which occurs in atopic subjects
subject with
1- positive past or family history of certain allergic diseases like bronchial asthma
2- allergic rhinitis