A historical essay on Paul Gerson Unna (1850—1929)

Abstract` The year 2025 marked the 175th anniversary of the birth of Paul Gerson Unna (1850—1929), a German dermatologist whose pioneering research and clinical practice had a profund impact on the development of dermatology. The publication of Unna’s fundamental work “The Histopathology of Skin Diseases” (Die Histopathologie der Hautkrankheiten, 1891) laid the groundwork for dermatopathology. Unna founded the journal “Dermatologische Wochenschrift” (later Dermatologica), which became one of the world’s leading dermatological periodicals. Unna was a pioneer in the use of new medications and treatment methods for skin diseases. He introduced salicylic acid, ichthyol, and other drugs that are still used in dermatology today. Thanks to the emulsifier Eucerit, suggested by Unna, Nivea cream was created. Paul Unna originated the idea of coated tablets, developed numerous new pharmacological agents in dermatology, and invented a special, highly effective dressing for treating trophic ulcers, which was named after him and survives to this day as the “Unna’s boot”. For his achievements, Paul Unna received numerous awards and titles. He was a member of many scientific societies and academies. A number of dermatological clinics and scientific institutions bear his name. Unna’s works remain highly relevant to this day.