Alfred Blaschko was a German dermatologist who was a native of Freienwalde an die Oder

Bad Freienwalde

Bad Freienwalde is a spa town in the Märkisch-Oderland district in Brandenburg, Germany. It is situated on an old branch of the Oder river at the northwestern rim of the Oderbruch basin, east of Eberswalde, and northeast of Berlin, near the border with Poland...

. In 1881 he earned his medical doctorate at Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, and afterwards worked with Georg Wegner (1843-1917) in Stettin. Later he opened a private dermatological practice in Berlin.

Blaschko specialized in the study of occupational dermatoses and prophylaxis of venereal disease. He performed studies of prostitution

Prostitution

Prostitution is the act or practice of providing sexual services to another person in return for payment. The person who receives payment for sexual services is called a prostitute and the person who receives such services is known by a multitude of terms, including a "john". Prostitution is one of...

 and examined the sanitary conditions in this profession.
In 1902 with Albert Neisser he co-founded the Liga zur Bekämpfung der Geschlechtskrankheiten (German Society for the Fight Against Venereal Diseases) in Berlin.

In 1901 at the Seventh Congress of the German Dermatological Society held in Breslau, Blaschko presented his observations concerning a rare dermatological condition. It involved patterned skin lesion

Lesion

A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

s that were linear on the extremities, S-shaped on the anterior trunk, and V-shaped on the back. Blaschko had based his findings on examinations of over 140 patients with nevoid and acquired linear skin diseases, which he then transposed the pattern of each patient onto dolls and statues. This unusual patterned condition was later referred to as lines of Blaschko. The embryological basis regarding the distribution pattern of the lines of Blaschko is considered a mystery, however they are thought to trace pathways of ectodermal cell development.