RegiSCAR DRESS Validation: Scoring system to determine the probability of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).
Fever ≥ 38.5°C
Enlarged Lymph Nodes
Eosinophilia
Internal Organs (~2 vs >2)
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
To accurately diagnose Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) / Drug-Induced Hypersensitivity Syndrome (DIHS).
Differentiates DRESS from simpler exanthematous drug eruptions or infective processes.
Section 2
Formula & Logic
Scoring Criteria
Fever ≥ 38.5°C (+1) or < 38.5°C (-1)
Enlarged lymph nodes at ≥ 2 sites (+1)
Eosinophilia: 0.7-1.49 x 10^9/L (+1); ≥1.5 x 10^9/L or ≥20% (+2)
Atypical lymphocytes (+1)
Skin involvement: Rash extent > 50% BSA (+1)
Skin rash suggesting DRESS: At least 2 of edema, scaling, purpura (+1)
Internal organ involvement: 1 organ (+1), ≥2 organs (+2)
Resolution duration > 15 days (+1)
Exclusion of other potential causes (e.g., ANA, blood cultures, viral serologies) (+1)
Interpretation
< 2: No DRESS
2 - 3: Possible DRESS
4 - 5: Probable DRESS
> 5: Definite DRESS
Section 3
Pearls/Pitfalls
Clinical Pearls
DRESS classically presents 2 to 6 weeks after drug initiation, significantly later than a morbilliform drug eruption.
Eosinophilia may be absent in the first few days of the rash. Serial complete blood counts (CBC) are mandatory.
Section 4
Next Steps
Clinical Management
Requires prompt discontinuation of suspected drug, thorough workup of liver/kidney/thyroid function, and typically systemic corticosteroids or other immunosuppressants depending on internal organ severity. Monitor for HHV-6 reactivation.
