| Feature | No | Yes | Unknown |
|---|---|---|---|
| Fever (≥ 338.5°C) | −1 | 0 | −1 |
| Enlarged lymph nodes (two sites or more, > 1 cm) | 0 | 1 | 0 |
| Atypical lymphocytes | 0 | 1 | 0 |
| Eosinophilia | |||
| 0.7 to 1.5 × 109/L or 10%–19% of white blood cell count | 1 | ||
| >31.5 × 109/L or ≥ 20% of white blood cell count | 2 | ||
| Skin rash | |||
| Distribution over more than 50% of body surface area | 0 | 1 | 0 |
| At least two of edema, infiltration, purpura or scale | −1 | 1 | 0 |
| Biopsy suggesting DRESS | −1 | 0 | 0 |
| Internal organ involved | |||
| One | 1 | ||
| Two or more | 2 | ||
| Resolution in more than 15 days | −1 | 0 | −1 |
| At least three negative results from biologic investigations into alternative diagnoses | 0 | 1 | 0 |
Note: DRESS = drug reaction with eosinophilia and systemic symptoms. Probability of a diagnosis of DRESS: < 2, unlikely; −3, possible; 4–5, probable; > 5, definite.
Adapted from Kardaun and colleagues.1