Laboratory Studies
The diagnosis of actinic purpura is usually obvious at clinical examination. Laboratory investigation is not required unless the diagnosis is not readily apparent.
Findings of the following tests are in the reference ranges:
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Complete blood cell count
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Coagulation studies
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Platelet count determination
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Liver function studies
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Urinalysis
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Stool guaiac test
Imaging Studies
Morphological analysis by in vivo reflectance confocal microscopy and ultrasonography may be useful in evaluating actinic purpura. [17]
Histologic Findings
Biopsy reveals a thinned epidermis with many abnormal keratinocytes in a disorderly pattern. The upper dermis contains extravasated red blood cells and hemosiderin without evidence of inflammatory cells. At histologic evaluation, solar elastosis can be appreciated in the surrounding skin as faintly blue homogenized elastotic material lying just below a layer of normal connective tissue at the base of the epidermis. The amount of abnormal elastic fibers is markedly increased, and the amount of collagen is decreased. About 10% in one study were found to have significant neutrophilic infiltration. [14] Inflammatory changes were found to be linked with clefting of elastotic stroma. The Gomori iron stain may be positive. [16]
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Actinic, or senile, purpura. Courtesy of José Reynaldo da Fonseca (own work), via Wikimedia Commons.
