Initial Workup and Treatment for a Patient Presenting with Rash

Essential History Components

The American College of Physicians recommends documenting the temporal relationship between the rash and new medications, exposures, or activities, as well as assessing the patient's medication review, occupational history, and associated symptoms 3
A complete medication review, including over-the-counter drugs and supplements, is crucial in identifying potential drug-induced causes, according to the Journal of Clinical Oncology 1, 2
The British Association of Dermatologists suggests that an occupational history, including work practices and products handled, is essential in determining potential workplace-related causes 4
Assessing associated symptoms, such as pruritus, burning, and tenderness, is vital in determining the severity of the rash, as recommended by the Journal of Clinical Oncology 1, 2

A full skin examination, including vital signs and evaluation of all skin surfaces and mucous membranes, is necessary to determine the severity of the rash, according to the Journal of Clinical Oncology 2
Calculating the percentage of body surface area (BSA) involved is crucial in determining the severity of the rash, as recommended by the Journal of Clinical Oncology 1, 2

The American Academy of Dermatology recommends obtaining a complete blood count and comprehensive metabolic panel if needed for differential diagnosis, as well as considering skin biopsy and patch testing for suspected allergic contact dermatitis 1, 2, 4
Serial clinical photography is recommended for monitoring progression, according to the Journal of Clinical Oncology 1, 2

The Centers for Disease Control and Prevention (CDC) recommends immediately excluding life-threatening conditions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS), as outlined in the MMWR Recommendations and Reports 5, 6
Monitoring for severe cutaneous adverse reactions (SCAR) and infection is crucial, according to the Journal of Clinical Oncology and the Annals of Internal Medicine 1, 2, 5, 6

For mild rash (<10% BSA, Grade 1), the American Academy of Dermatology recommends applying topical emollients and mild-to-moderate potency topical corticosteroids, as well as avoiding skin irritants, according to the Journal of Clinical Oncology and Praxis Medical Insights 1, 2, 7
For moderate rash (10-30% BSA, Grade 2), considering holding the offending agent, applying medium-to-high potency topical corticosteroids, and using oral antihistamines is recommended, according to the Journal of Clinical Oncology and Praxis Medical Insights 1, 2, 7
For severe rash (>30% BSA with moderate-severe symptoms, Grade 3), holding the offending agent immediately, applying high-potency topical corticosteroids, and using oral prednisone is recommended, according to the Journal of Clinical Oncology 1, 2
For life-threatening rash (Grade 4), immediate hospitalization, holding all suspected causative agents permanently, and using IV methylprednisolone is recommended, according to the Journal of Clinical Oncology and the MMWR Recommendations and Reports 1, 2, 5, 6

Referring to dermatology if autoimmune skin disease is suspected, if there is no response to initial treatment after 2 weeks, or if diagnostic uncertainty exists is recommended, according to the Journal of Clinical Oncology and Praxis Medical Insights 1, 2, 7

The CDC recommends avoiding prophylactic corticosteroids, as they may increase the incidence of rash, according to the MMWR Recommendations and Reports 5, 6
The American Geriatrics Society suggests avoiding sedating antihistamines in elderly patients due to the risk of falls and cognitive impairment, according to Praxis Medical Insights 7
The American Academy of Dermatology recommends avoiding crotamiton, capsaicin, or calamine for pruritus management, according to Praxis Medical Insights 7

The CDC recommends being aware of drug-induced rashes, which most commonly occur with NNRTIs (nevirapine, efavirenz), abacavir, and amprenavir within the first weeks of therapy, according to the MMWR Recommendations and Reports 5, 6
The British Association of Dermatologists suggests identifying and eliminating irritants or allergens in cases of contact dermatitis, according to the British Journal of Dermatology and Praxis Medical Insights 4, 7