Table 2 Distinguishing Features of Irritant and Allergic Contact Dermatitis
Feature | Irritant Contact Dermatitis | Allergic Contact Dermatitis |
|---|---|---|
Pathogenesis | Direct cytotoxic effect | T cell-mediated immune reaction |
Affected individuals | Everyone | A minority of individuals |
Onset | Immediate (chemical burns) | 12-48 h in previously sensitized individuals |
| Â | After repeated exposure to weak irritants | Â |
Signs | Subacute or chronic eczema with desquamation, fissures | Acute to subacute eczema with vesiculation |
Symptoms | Pain or burning sensation | Pruritus |
Concentration of contactant | High | Low |
Investigation | None | Patch or prick tests |