Discriminating minor and major forms of drug reaction with eosinophilia and systemic symptoms: Facial edema aligns to the severe phenotype

Background Drug reaction with eosinophilia and systemic symptoms (DRESS) is a cutaneous and systemic drug allergy disorder. Patients exist on a severity spectrum, with some experiencing a mild form of the disorder that fails to meet the Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs diagnostic criteria for DRESS. Objective We sought to determine whether there were any cutaneous or dermatopathologic features that discriminate between the mild form of DRESS (DRESS minor) and the severe phenotype (DRESS major). Methods Hospitalized patients from a single center with a diagnosis of DRESS were prospectively recruited over a 7-year period. Clinical and dermatopathologic features were analyzed to discriminate between DRESS minor and DRESS major. Results Forty-five patients were included, of whom 19 had a Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs score of ≤3 (DRESS minor) and 26 had a score of ≥4 (DRESS major). The mean latency period (P = .001), fever >38.5 °C (P = .001), and a reaction lasting >15 days (P = .010) discriminated DRESS major from DRESS minor. Facial edema was the sole discerning cutaneous feature (P = .025). Discriminating histopathologic features included basal squamatization (P = .005), dermal red blood cell extravasation (P = .009), and interface inflammation (P = .005). Conclusion We propose a new classification system—DRESS minor—to distinguish the milder illness from the severe form, DRESS major. Facial edema and certain histopathologic features can help discriminate between major and minor versions.