Teasing Out the Characteristics of Targetoid Rashes

Targeted or targetoid rashes are one specific rash presentation that is commonly seen and occurs with at least three conditions. Other conditions have target-like lesions, but by far the most common are acute annular urticaria or urticaria multiforme, erythema multiforme, and serum sickness-like rashes (SSLR).   Unlike true serum sickness, SSLR is not a type III reaction, and frank arthritis, hypocomplementemia, vasculitis, and nephropathy are not typically seen. These rashes have significant overlap in presentation and appearance, and they are frequently confused for each other. Nevertheless, it is possible to tease out unique characteristics that allow the clinician to differentiate among the three conditions.   The classic skin lesion of erythema multiforme is a target or iris lesion characterized by concentric erythematous rings separated by rings of near-normal color. The lesion size may range from 2 mm to 20 mm. The other conditions have lesions that appear similar and present as annular and polycyclic wheals with central clearing or ecchymotic or purpuric centers.   We were able to capture in the videos below visual images and historical accounts of two different patients presenting with targetoid lesions that were most consistent with urticaria multiforme and serum sickness-like conditions.   Click here to watch Dr. Mellick diagnose targetoid rashes on arms and legs.   Click here to watch Dr. Mellick diagnose the urticarial multiforme rash.   Dr. Mellick is ...
Source: M2E Too! Mellick's Multimedia EduBlog - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs