Drug eruption: severity signs and tests

• No routine laboratory tests: stop the suspected drug, review the patient, look for warning signs.
• FBCif needednon-French guidelineIn the United States, the 2022 practice parameter allows continuing, under H1 antihistamines and topical corticosteroids, an urgent drug that is more effective than its alternatives, in case of benign exanthema; it lists raised liver enzymes and impaired kidney function among the signs for stopping, without setting a frequency ^[2]. DermNet (New Zealand) cites FBC, liver, kidney and CRP when tests are discussed ^[3]. No French recommendation cited covers this case; the DRESS PNDS (French national protocol for diagnosis and care) asks to identify the suspect drug early and stop it ^[4].
• ASTif needednon-French guidelineIn the United States, the 2022 practice parameter allows continuing, under H1 antihistamines and topical corticosteroids, an urgent drug that is more effective than its alternatives, in case of benign exanthema; it lists raised liver enzymes and impaired kidney function among the signs for stopping, without setting a frequency ^[2]. DermNet (New Zealand) cites FBC, liver, kidney and CRP when tests are discussed ^[3]. No French recommendation cited covers this case; the DRESS PNDS (French national protocol for diagnosis and care) asks to identify the suspect drug early and stop it ^[4].
• ALTif needednon-French guidelineIn the United States, the 2022 practice parameter allows continuing, under H1 antihistamines and topical corticosteroids, an urgent drug that is more effective than its alternatives, in case of benign exanthema; it lists raised liver enzymes and impaired kidney function among the signs for stopping, without setting a frequency ^[2]. DermNet (New Zealand) cites FBC, liver, kidney and CRP when tests are discussed ^[3]. No French recommendation cited covers this case; the DRESS PNDS (French national protocol for diagnosis and care) asks to identify the suspect drug early and stop it ^[4].
• Serum creatinineif needednon-French guidelineIn the United States, the 2022 practice parameter allows continuing, under H1 antihistamines and topical corticosteroids, an urgent drug that is more effective than its alternatives, in case of benign exanthema; it lists raised liver enzymes and impaired kidney function among the signs for stopping, without setting a frequency ^[2]. DermNet (New Zealand) cites FBC, liver, kidney and CRP when tests are discussed ^[3]. No French recommendation cited covers this case; the DRESS PNDS (French national protocol for diagnosis and care) asks to identify the suspect drug early and stop it ^[4].

Laboratory tests (urgent)

• FBC (eosinophils, atypical lymphocytes)
• AST
• ALT
• Serum creatinine with eGFR

Urine tests

• Urine dipstick (proteinuria)

Laboratory tests

• FBC (neutrophilia)
• CRP
• AST
• ALT
• Serum creatinine with eGFR

• No tests in the community: stop the suspected drug and refer urgently (SAMU, expert centre for severe drug eruptions).