From the Guidelines
The diagnostic workup for a patient with a rash and potential systemic involvement should include a total body skin examination, complete review of systems, and laboratory tests such as CBC with DIFF, liver, and kidney function tests, as well as consideration of skin biopsies and serial clinical photography. This approach is supported by the most recent and highest quality study, which emphasizes the importance of a thorough evaluation to rule out other etiologies of the skin problem and to assess for potential systemic involvement 1.
Key Components of Diagnostic Workup
- Total body skin examination with attention to examining all mucous membranes
- Complete review of systems to assess for potential systemic involvement
- Laboratory tests, including:
- CBC with DIFF
- Liver function tests
- Kidney function tests
- Consideration of urinalysis (UA) in the context of DRESS to assess for associated nephritis
- Consideration of skin biopsies to assess for full-thickness epidermal necrosis or other possible etiologies
- Serial clinical photography to monitor the progression of the rash
Additional Considerations
- Rule out other etiologies of the skin problem, such as infection, effect of another drug, or skin condition linked to another systemic disease 1
- Consider referral to a dermatologist if autoimmune skin disease is suspected 1
- Consider clinical monitoring with use of serial clinical photography 1
- If mucous membrane involvement or blistering is noted on the skin, consider early admission to a burn center for further monitoring and management 1
From the Research
Diagnostic Workup for Rash with Potential Systemic Involvement
To approach a patient with a rash and potential systemic involvement, a thorough diagnostic workup is essential. The following steps can be considered:
- Complete Blood Count (CBC): A CBC is a fundamental test that can provide valuable information about the patient's condition. It evaluates the total numbers and characteristics of cell components in the blood, including white blood cell (WBC) count, neutrophil-to-lymphocyte ratio (NLR), hemoglobin (Hb) level, mean corpuscular volume (MCV), red cell distribution width (RDW), platelet count, mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) 2.
- Physical Examination: A thorough physical examination is crucial to assess the extent and characteristics of the rash, as well as to identify any other signs of systemic involvement.
- Medical History: Obtaining a detailed medical history can help identify potential underlying causes of the rash and systemic symptoms.
- Additional Tests: Depending on the patient's presentation and medical history, additional tests such as blood cultures, serologic tests, or imaging studies may be necessary to rule out specific conditions.
- Dermatological Examination: A dermatological examination can help determine the type and cause of the rash, and may involve procedures such as skin biopsies or scrapings.
- Systemic Involvement Evaluation: Evaluation for systemic involvement may include tests such as liver function tests, renal function tests, or inflammatory marker tests, depending on the suspected underlying condition 2.