It seems like we are talking about a hair disease which used to be known as Plica polonica, or Polish plait. Not surprisingly, in Germany this was also called Judenzopf. See, for example, this entry from a fascinating German-English dictionary printed in the 1790s in Leipzig (compiled by John Ebers):
If you want to really enhance your day, here are some other entries in that dictionary that you can read:
Interestingly, in various medical books and journals of the 19th century I've seen it asserted that this was actually uncommon among Jews. Of course we have to take all of it with a grain of salz given the nature of the discussions about what they saw as barbarian's diseases.
Here are two examples:
The different names given to the plica indicate more or less the ideas that prevail regarding its nature. The poles call it gwozdiec or gwodziec, which signifies a nail that splits the wood into which it is driven. In the district of the Roxolans it is termed koltun, a stake. In Germany superstitious fancies have also given it various curious denominations. It is called alzopf and schraitelzopf, as being the result of the malefices of vampires and incubi. By some it is asserted that the Moravians, natural enemies of the Poles, not having been able to conquer them by their arms, had recourse to magical art to inflict this scourge; hence they term it mahrenflechten, mahrenwichtung. To this day it is called hexenzopf and bichteln, or unbaptised, alluding, no doubt, to the Jews, who were accused of having introduced the disorder in the deadly hate they bore the Christians; hence was it also known by the name of Judenzopf (Coma Judaeorum).and:
Plica judaica, Judenzopf, are commonly met with in writers, and yet I was informed by my colleagues, in Cracow, that the plica was rarely to be met with among the tribes of Israel. If such be the case, it affords negative evidence, at least, to the opinion that this malady is engendered by filth alone; for if there is a mass of living filth in human shape, it is to be found in a Polish Jew, who stalks up and down the streets in a long gown, and fur cap upon his head, nor changes his gabardine till it falls piecemeal off his body, rotted by age. His long flowing hair, falling m ringlets upon his shoulders, and curling at the extremity, would seem to offer a fine nursery for plica: still, as I was informed, he is seldom attacked by this disease, but enjoys, as a substitute more generally diffused over his body, the psoriasis. It was not asserted that no cases are to be found among the Jews of this malady, but that there were but few, comparatively with the peasants. I recollect seeing but one Jew affected with plica, during the time I remained at Cracow.In 1831 Luigi Chiarini (aka Louis, Ludwig, etc.) printed the first two volumes of his translation of the Talmud into French. Chiarini (1789-1832), an Italian-born cleric, was a professor at the University of Warsaw, and the official censor of Hebrew books. He was not particularly a fan of Judaism or the Talmud. In fact, his translation was partly the catalyst for Moses Ephraim Pinnner's proposed translation (of which, like Chiarini, only the first tracate, Berachot, ever appeared). Many of the Jewish scholars of the day were particularly chagrined by Chiarini's work. For example, Leopold Zunz wrote a short book refuting Chiarini's earlier publication "Theorie du Judaisme."
In his translation, Chiarini gives the following as a note to our piece about פתויי הראש:
Although Chiarini translated the Gemara as "quelqu'un qui a la tête trop large" or his "head is too large," the footnote, above, is a translation of Rashi. The only thing to point out is that he gave the la'az (langue barbare) as Platider. Above, I used feltrer, following Moshe Kattan's Otzar Lo'azei Rashi, which made use of all the earlier sources, like Darmester and Blondheim.
What does Chiarini add? "Il serait done prouvé par ce passage que la Plica Polonica devrait être plutôt appelée Plica Judaica," "It could therefore be proved by this passage that Plica polonica should instead be called Plica judaica." Normally I would let this go without comment, since it speaks for itself, but sometimes people tell me to spell things out explicitly: this Talmudic passage is not speaking about Jews or non-Jews, but rather people in general. It mentions a כושי, an African person, which I suppose was unusual to see. It should also be pointed out, as alluded to in the post's title, that Chiarini was employed in Poland. One imagines that some Poles were not thrilled that the rest of Europe named a peasant's hair condition after them.
Shortly thereafter, the Gemara mentions a blessing to make when one sees an elephant, an ape, or a קפוף, which Rashi elsewhere translates as an owl (Soncino gives "a long-tailed ape", same as Jastrow). Chiarini approves of Rashi and translates an an owl, which has some facial resemblance to a human. What does he write in the notes? "Le Koran sert de Commentaire au Talmud lorsqu'il parle fi souvent des hommes changés en singes et en d'autres animaux," "The Koran is a Talmudic commentary, often speaking of men changed into apes and other animals."
For more on Chiarini, see Roman Marcinkowski "Luigi Chiarini (1789-1832) - An Anti-Judaistic Reformer of Judaism" Studia Judaica 7 (2004) 237-248.