Most dermatologic emergencies presenting to the ED involve skin lesions resulting from infections, irritants, and allergic etiologies, with a smaller subset related to malignancy.1 Visual pattern recognition is the key to diagnosis. The recommended approach for the diagnosis of a skin disorder in the ED (assuming resuscitation or stabilization is not required) is to:
Determine the chief complaint.
Obtain a brief history (duration, rate of progression, and location of lesions).
Perform the dermatologic examination (morphology and extent of distribution).
Formulate the age-appropriate differential diagnosis based on lesion morphology and distribution.
Elicit additional concerns from the history (associated complaints, comorbidity, medications, or exposures), and include or exclude syndromes in the differential diagnosis based on this information.
Evaluate for systemic involvement, and consider ancillary investigations, if necessary.
Obtain dermatologic consultation, if necessary, and arrange for appropriate referral (primary care or dermatologic).
Determine the chief complaint and obtain a brief history (discomfort, duration, rate of progression, percentage of body surface involvement, and location of lesions). The secondary history should include issues relating to the lesion: morphology, evolutionary nature, rate of progression, and distribution. Associated systemic complaints and mucosal systems must be identified. Ask about exposures, immunizations, toxins, chemicals, foods, animals, insects, plants, and ill contacts. Review sexual history, if appropriate, and medical and family histories. If applicable, obtain a detailed occupational history as industrial exposure may be causative. Asking about medication use, sun exposure, travel history, or particular food ingestion also may yield helpful information. Be sure to include any other housemates or partners in your history of exposures; contact dermatitis can occur from exposure to fragrances or other products that a partner is using.2 The patient should also be asked about the degree of discomfort of the dermatoses; a painful dermatitis is often a red flag and may not be associated with a self-limiting lesion.3
A detailed medication history is important, and particular attention should be paid to recently started drugs or dosage increases. Erythema multiforme, exfoliative dermatitis, photosensitivity reactions, toxic epidermal necrolysis, and vasculitis are common medication-induced drug reactions. Dermal necrosis should prompt consideration of anticoagulant use, whereas a diffuse rash in a patient on sulfa drugs, anticonvulsants, or some antimicrobials may aid the clinician in diagnosing Stevens-Johnson syndrome, drug reactions with eosinophilia and systemic symptoms, or toxic epidermal necrolysis.
The patient should be gowned and in a room with adequate lighting and appropriate privacy to allow entire skin examination. Inspect all skin and mucosal surfaces, including hair, nails, scalp, and mucous membranes. Then evaluate the specific skin lesions. A magnifying lens and a portable light are helpful aids.
Examine the skin systematically. Determine the distribution, pattern, arrangement, morphology, extent, and evolutionary changes of the lesions. Distribution is the location of the skin findings, and the pattern is their anatomic, functional, ...