Contact dermatitis denotes superficial inflammation of the skin induced by exogenous chemicals interacting on the skin.
Like other forms of dermatitis contact dermatitis can represent any of the three phases: acute, subacute or chronic. One form may merge into another form by evolution.
On the basis of etiopathogenesis contact dermatitis can be of two types: irritant contact dermatitis and allergic contact dermatitis.
PHASES OF CONTACT DERMATITIS
Although the two types of contact dermatitis differ conceptually their cellular and cytokines profiles bear very close resem-blance. Their basic difference is in the antigen specificity; allergic contact dermatitis possesses this specificity whereas irritant contact dermatitis does not possess this.
Comparison between Irritant and Allergic Contact Dermatitis |
Irritant contact dermatitis | Allergic contact dermatitis | ||
---|---|---|---|
1. | Antigen-specificity | Non-specific | Specific |
2. | Sensitization | Not required | Required |
3. | Genetic predisposition | Not present | Present |
4. | Pruritus | Not marked (early) | Marked |
5. | Pain/Burning | Pronounced (early) | Less pronounced |
6. | Vesicles | Not common | Common |
7. | Pustules | Common | Not common |