A histologic and immunohistochemical study of chilblains

Background: The histopathologic diagnosis of chilblains is controversial an d the histologic changes are often considered nonspecific, mainly because t hey are poorly documented. Although a dermal inflammation in chilblains has been noticed, the infiltrate has not yet been characterized. Objective: Our purpose was to analyze microscopic and immunohistochemical f indings in a large series of chilblains and to compare the results with tho se of lupus erythematosus (LE). Methods: We included 36 cases of clinically typical chilblains of the hands , of which 17 were thoroughly investigated to rule out cryopathy or LE. Ten biopsy specimens of hand lesions from patients with proven LE were include d as controls. All slides were analyzed by conventional microscopy and by i mmunohistochemistry with anti-CD3, anti-CD20, and anti-CD68 antibodies. Results: The most characteristic finding in chilblains (47% of cases) was t he association of edema and reticular dermis infiltrate that showed a perie ccrine reinforcement. Such a combination of changes was not observed in LE. Epidermal changes in chilblains consisted mainly in necrotic keratinocytes in 52% of cases. The comparison of 17 idiopathic chilblains with LE showed significant differences in spongiosis (58% vs 0% respectively), vacuolatio n of basal layer (6% vs 60%), edema of the dermis (70% vs 20%), and deep pe rieccrine inflammation (76% vs 0%). Immunohistochemistry showed that the in filtrate was composed of a majority of T cells associated with macrophages and a few B lymphocytes. The same pattern was observed in both chilblains a nd LE. Conclusion: Our results show that a predominantly T-cell papillary and deep infiltrate with a perieccrine reinforcement, associated with dermal edema and necrotic keratinocytes, are the hallmarks of chilblains of the hands. T hese changes can help differentiate idiopathic perniosis from LE; immunohis tochemistry is of no use in differentiation.