Table 1 Reading of patch test reactions according to International Contact Dermatitis Research Group guidelines
Score | Patch test reaction | Criteria |
|---|---|---|
- | Negative | No reaction |
+? | Doubtful | Faint erythema only |
+ | Weak | Erythema, infiltration, possibly papules |
++ | Strong positive | Erythema, infiltration, papules, vesicles |
+++ | Extreme positive | Intense erythema and infiltration and coalescing vesicles |