Pattern-Specific Loss of Desmoplakin I and II Immunoreactivity in Erythema Multiforme and its Variants: A Possible Aid in Histologic Diagnosis

Erythema multiforme

Erythema multiforme is an inflammatory skin and mucosal disease mainly related to infectious agents such as Herpes simplex virus, Mycoplasma pneumoniae, though it can also be "idiopathic". The characteristic skin lesions are typical or atypical acral raised target lesions. The oral mucosa can be affected, alone or in combination with other mucosal/cutaneous sites, sometimes causing extreme pain, severely impacting food intake, and warranting hospitalization. A comprehensive understanding of erythema multiforme clinical characteristics, triggering agents, and differential diagnosis including Stevens-Johnson syndrome/Toxic Epidermal Necrolysis, is crucial to conduct proper workup and management. Mycoplasma pneumoniae infection should be immediately ruled out because of the need of antibiotics. The cornerstone of management is symptomatic treatment and will be detailed in this review as well as the etiologic treatment. Lastly, the management of persistent or recurrent erythema multiforme can be challenging, especially when antivirals fail to prevent a relapse, but breakthrough treatments have been reported successful in this difficult-to-treat subset of patients.

Funding

The Funding was provided by the University of Sherbrooke Faculty of Medicine and Health Sciences.

Desmoplakin I/II immunohistochemical staining may be a helpful tool in differentiating cutaneous graft versus host disease from the erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis spectrum disorders

Cutaneous graft versus host disease (cGVHD) has substantial clinical and histopathologic overlap with erythema multiforme (EM), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). This overlap can make it difficult to distinguish these disorders in patients who have received hematopoietic transplants. We sought to evaluate the utility of Dp I/II immunohistochemical stain in differentiating EM/SJS/TEN and cGVHD in a large cohort. Skin biopsy specimens from patients with cGVHD (n = 58) and EM/SJS/TEN (n = 60) were evaluated for Dp I/II expression by immunohistochemistry. We found a statistically significant difference in Dp I/II staining between cGVHD (all grades) and EM/SJS/TEN (mean scores 1.62 and 2.14, respectively; p < 0.005), as well as between Grades 2 + 3 cGVHD and EM/SJS/TEN (mean scores 2.26 and 1.62, respectively; p < 0.005), while we did not find a significant difference between Grade 4 cGVHD and EM/SJS/TEN (mean scores 1.69 and 1.62, respectively; p = 0.71). Dp I/II immunostain may be useful for differentiating EM/SJS/TEN from Grade 2 and Grade 3 cGVHD, especially in clinically ambiguous cases without extracutaneous GVHD.