Black Dermographism

The patient, a 75 year-old man noted a blackish under his right sideburn for a couple of weeks.  He googled black marks on the skin and became anxious regarding the possibly of skin cancer, in particular melanoma.

O/E:  Dark greenish-black area with ill-defined borders.

When asked to see his eyeglasses:

an alcohol prep pad was rubbed over the area:

and the pigment disappeared:

The patient was embarrassed and left the office smiling and profoundly relieved.

Diagnosis:  Thisis an example of "black dermographism."
Cyberchondria exacerbated the patient's anxiety prompting the office visit.  Cyberchondria is a 21st Century illness syndrome that we see daily in our practices..


Comment:  From Visual Diagnosis on Black Dermographism

The term "black dermographism" designates the fact that under certain conditions a well defined black line appears where the skin is stroked with certain metals.This phenomenon was first reported by the Russians Emdin and Kusmenko1 in 1925. They contrasted the well known red and white dermographisms with black dermographism and stated that only the latter was to be regarded as a true one, i. e. "actual writing on the skin," since both the white and red dermographisms are due to stimulation of the nerve and muscle fibers of the blood vessels of the skin.According to these authors, the black "writing" which appears on the skin following application of certain blunt metallic implements with moderate pressure represents not a chemical but a physical process due to the particles of the metal rubbed off by friction and remaining on the skin. While they originally assumed that a hysterical condition.

References:
1. Black Dermographism

Erin Lowe, DO; Scott Lim, DO

JAMA Dermatol. 2017;153(3):352-353