The role of histological presentation in erythroderma.

BACKGROUND: Erythroderma is a serious medical condition characterized by inflamed red skin involving over 90% of the body. It can be the common presentation of different diseases, therefore clinical diagnosis can be problematic. Controversial data are reported regarding the diagnostic value of histological examination in erythroderma subjects.

METHODS: A retrospective study was performed, investigating histological skin specimens of patients with a clinical diagnosis of erythroderma admitted to the Department of Dermatology of State Pediatric Medical University, Saint Petersburg, from 2001 to 2014. Histopathology examination was performed in each case by a pathologist with a special interest in the skin disease who was blind to any clinical information as well as to final diagnosis.

RESULTS: Blinded histopathology examination alone was able to give the correct diagnosis in 61% (n = 50/82) of cases when compared to final diagnosis. A diagnosis of psoriasis was made in 23.2% (n = 19/82) of subjects, spongiotic dermatitis/eczema in 20.7% (n = 17/82), mycosis fungoides in 8.5% (n = 7/82), and drug eruption in 8.5%; histological diagnosis was inconclusive or not matching the final diagnosis when available in the remaining 39.1% of cases (n = 32/82).

CONCLUSION: Erythroderma remains a condition difficult to study and treat. We showed that a correct judgment about its cause can be based on objective histopathological criteria in up to 60% of cases. More studies are needed to try to find out further histological and/or immunohistochemical markers that could help the clinician with the erythroderma etiology diagnostic process.