Trained as a teacher and later passing an examination to be a principal, Trosse began her career working in public schools and as a private tutor.

[1][3] Trosse began her career working as a teacher at the Gransee public school and then taught at the women's gymnasium in Gnesen.

[3] In 1893, she opened a girl's boarding school with Hermine Dulsmann, the Baroness von Bardeleben, in Bad Neuenahr.

[5] In 1895, Trosse began publishing a series of works examining homosexuality and seeking to redefine the scientific definition of natural sexuality.

Her first publication Der Konträrsexualismus in Bezug auf Ehe und Frauenfrage (Contrary-sexuality in relation to marriage and the women question), was the first work written by a German woman on the topic.

[8] In 1896, Trosse published two articles in English on ancient medical knowledge written about by Alexander of Tralles, Burnt Substances and Sources of the Drugs Supplied to the Greeks.

[13] Because German law forbade married women to teach, she lost her employment upon her marriage[1] and became a clinician in the diabetes clinic the couple founded.

[5][14] In 1923, after returning from the war, her husband died[3] and his cousin, Ludwig Külz moved to Bad Neuenahr to take over operation of the clinic.

His morphine addiction impaired his abilities,[15][16] and Külz-Trosse struggled with keeping the facility open, until her daughter married a physician, Erwin Quednow, who took over running the clinic.