ECZEMA VIRUS

Eczema is a form of dermatitis, or inflammation of the upper layers of the skin. The term eczema is broadly applied to a range of persistent or recurring skin rashes characterized by redness, skin edema, itching and dryness, with possible crusting, flaking, blistering, cracking, oozing or bleeding. Areas of temporary skin discoloration sometimes characterize healed lesions, though scarring is rare.

The cells of the immune system work in various ways in skin disease. The rash that occurs after being stung by some insects happens within minutes of contact. It is due to the release of chemicals such as histamine by immunity cells within the skin layers. This is known as ‘immediate hypersensitivity’.

Slower acting forms of response by the immune system occur because the population of cells that react against the invading substance or organism (allergen) needs to be built up from a small number of ‘memory’ cells that recognise the allergen.

Two or three days these cells give rise to others that in turn switch on other defense mechanisms such as the release of chemicals that attract the scavenger cells of the immune system. Because of the lag between initial contact and subsequent reaction, this is called ‘delayed hypersensitivity’. The skin reactions underlying allergic contact eczema are of this type.