Diascopy Explained

Diascopy is a test for blanchability performed by applying pressure with a finger or glass slide and observing color changes.^{[1] [2] [3] [4]}

It is used to determine whether a lesion is vascular (inflammatory or congenital), nonvascular (nevus), or hemorrhagic (petechia or purpura). Hemorrhagic lesions and nonvascular lesions do not blanch ("negative diascopy"); inflammatory lesions do ("positive diascopy"). Diascopy is sometimes used to identify sarcoid skin lesions, which, when tested, turn an apple jelly color.

Notes and References

1. Marks, James G; Miller, Jeffery (2006). Lookingbill and Marks' Principles of Dermatology (4th ed.). Elsevier Inc. Page 29. .
2. Investigative and clinical studies with diascopy in dermatology. L.. Goldman. H.. Plotnick. I.. Balinkin. May 9, 1957. Archives of Dermatology. 75. 5. 699–705. PubMed. 10.1001/archderm.1957.01550170067012. 13410135.
3. Clinical value of diascopy and other non-invasive techniques on differential diagnosis algorithms of oral pigmentations: A systematic review. Pérez-López. D. Peña-Cristóbal. M. Otero-Rey. EM. Tomás. I. Blanco-Carrión. A. October 1, 2016. Journal of Clinical and Experimental Dentistry. 8 . 4 . e448–e458 . 10.4317/jced.53005 . 27703615. 5045694 .
4. Diascopy: a clinical technique for the diagnosis of vascular lesions. M.. Rudd. R.. Eversole. W.. Carpenter. March 9, 2001. General Dentistry. 49. 2. 206–209. PubMed. 12004702.