Emergency clinicians are commonly presented with dermatologic complaints. This article discusses the approach to emergency diagnosis and treatment of uncommon but life-threatening inflammatory and immune-mediated dermatologic diseases, including erythema multiforme (EM), Stevens-Johnson syndrome\/toxic epidermal necrolysis (SJS\/TEN), and cutaneous vasculitis. Sterile neutrophilic dermatosis (Sweet-like syndrome) and canine acute eosinophilic dermatitis with edema (Wells-like syndrome) are described due to their acute nature and concurrent systemic signs. The more common but less serious conditions of urticaria and angioedema are also described.<\/p>\n
Take-Home Points<\/strong><\/p>\n The\u00a0Insights in Dermatology<\/a>\u00a0series is brought to you by\u00a0Nextmune<\/a>.<\/p>\n Dermatologic disease commonly prompts dog owners to present their pets to an emergency clinician. Although uncommon, true life-threatening dermatologic emergencies exist, and early recognition is important for long-term survival.<\/span><\/p>\n Erythema multiforme (EM) and Stevens-Johnson syndrome\/toxic epidermal necrolysis (SJS\/TEN) are diseases in which keratinocyte cell death causes erosion and\/or <\/b>ulceration. Patients with SJS\/TEN have especially extensive lesions where necrosis is a common feature, and the loss of large areas of skin can be life threatening. <\/span><\/p>\n Cutaneous vasculitis may alert the clinician to the development of systemic <\/span>vasculitis and can cause severe lesions, including necrotic lesions at the extremities, ears, and tail tips. Some dogs with vasculitis may be systemically ill, depending on the size and site of the vessels attacked. <\/span><\/p>\n Sterile neutrophilic dermatosis (Sweet-like syndrome or SLS) may cause acute development of erythematous skin <\/span>lesions in association with significant systemic infiltrate. Canine acute eosinophilic dermatitis with edema (CAEDE or Wells-like syndrome) typically presents as the development of acute gastrointestinal signs, followed later by development of erythematous lesions on the skin. Angioedema and urticaria are more common but less likely to be life threatening. <\/span><\/p>\n This article outlines the major features of each disease, along with best practices for diagnosis and management in an emergency setting.<\/span><\/p>\n EM and SJS\/TEN are characterized by cytotoxic T-lymphocyte targeting of keratinocytes at all layers of the epidermis.1,2<\/sup> These are considered by some to be diseases along a continuous spectrum in veterinary patients, with EM the mildest, followed by SJS, then TEN; however, others consider canine EM to be a separate disease from SJS\/TEN.1<\/sup> Clear clinical criteria for diagnosis and distinction of EM and SJS\/TEN in veterinary medicine are not yet completely established and are largely adopted from human medicine.1<\/sup><\/span><\/p>\n Clinical lesions of EM are highly variable and may consist of ulcers, crusts, and erythematous macules or papules.1<\/sup> Central pallor or purpura may be seen, but classic \u201ctarget\u201d lesions are uncommon.1<\/sup> Lesions are often well demarcated and may be polycyclic, arciform, or serpiginous (<\/span>FIGURES 1 AND 2<\/b><\/span>).1<\/sup> Distribution is most often truncal, particularly in the axillary and inguinal regions (FIGURE<\/b><\/span><\/span>\u00a03<\/b><\/span>).1<\/sup> In some cases, lesions may involve mucocutaneous junctions, paw pads, and pinnae (FIGURE<\/b><\/span><\/span>\u00a04<\/b><\/span>).1<\/sup> Patients with EM may show systemic signs, including fever, anorexia, lethargy, and depression, or their signs may be limited to the skin.1,3<\/sup><\/span><\/p>\n\n
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\n<\/div>\nErythema Multiforme and Stevens-Johnson Syndrome\/Toxic Epidermal Necrolysis<\/h2>\n
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Figure 1. Chronic erythema multiforme in a 4-year-old female spayed pit bull mix with polycyclic and arciform ulcers and crusts on the ventrum. Initial onset was associated with cephalexin, but there was no improvement with drug withdrawal.<\/span><\/a><\/div><\/div>![\"\"](\"https:\/\/navc.sitepreview.app\/todaysveterinarypractice.com\/wp-content\/uploads\/sites\/4\/2023\/08\/Brame_TVPSepOct23_DermEmergenciesPt2_Fig2-768x1024.png\")
Figure 2. Erythema multiforme in a 5-year-old female spayed Maltese-Yorkshire terrier cross with polycyclic to serpiginous ulcers, crust, and scale. Courtesy Lindsey Citron, University of Pennsylvania.<\/span><\/a><\/div><\/div>
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![\"\"](\"https:\/\/navc.sitepreview.app\/todaysveterinarypractice.com\/wp-content\/uploads\/sites\/4\/2023\/08\/Brame_TVPSepOct23_DermEmergenciesPt2_Fig4.png\")