The Polish plait usually results from deficient hair care. Uncombed hair becomes irreversibly entangled, forming a matted, malodorous and encrusted or sticky moist mass. It may be caused by or accompanied with lice infestation (pediculosis) and lead to inflammation of the scalp. The Polish plait is typically a (sometimes large) head of hair, made of a hard impenetrable mass of keratin fibers permanently cemented together with dried pus, blood, old lice egg-casings and dirt. The disease may be easily prevented by standard hygienic practices, such as washing and combing of the hair. Treatment involves cutting the affected hair.
Due to superstitious beliefs, the Polish plait used to be particularly common in Poland, hence its name. (In German it is called a Weichselzopf, a Vistula plait, which names it after one region of Poland.) Initially, the plait was treated as an amulet, supposed to bring good health. For this reason people not only allowed it to develop, but even encouraged it. Spreading fat on their hair and wearing wooly caps even in summer were common practices.
In the early 17th century people began to believe plaits were an external symptom of an internal illness. A growing plait was supposed to take the illness "out" of the body, and therefore it was rarely cut off; in addition, the belief that a cut-off plait could avenge itself and bring an even greater illness discouraged some from attacking it. It was also believed that casting a magic spell on someone could cause that person to develop a Polish plait, hence also the name elflock was used in English.
These convictions were so widespread and strong that many people lived their whole lives with a Polish plait. A plait could sometimes grow very long – even up to 80 cm. Polish plaits could take various forms, from a ball of hair to a long tail. Plaits were even categorized in a quite sophisticated way; there were plaits "male" and "female", "inner" and "outer", "noble" and "fake", "proper" and "parasitical".
A British diarist and Samuel Johnson's friend, Hester Thrale, in her book Observations and reflections made in the course of a journey through France, Italy, and Germany, describes a Polish plait she saw in 1786 in the collection of the Elector of Saxony in Dresden: "the size and weight of it was enormous, its length four yards and a half [about 4.1 m]; the person who was killed by its growth was a Polish lady of quality well known in King Augustus's court."
In the second half of the 19th century some intellectuals waged a war against superstition and lack of hygiene among the peasantry. Many plaits, often to the horror of their owners, were cut off. In Western Galicia, it was Professor Józef Dietl who made a particular effort to examine and treat Polish plaits. He organized an official census of people suffering from the disease, which spawned rumors that plaits would be taxed. Those rumors were said to have helped eradicate the Polish plait in the region. A huge preserved Polish plait can be seen in the History of Medicine Museum in Kraków (photo). The Polish word for the Polish plait, kołtun, is now used figuratively in Poland to denote an uneducated person with an old-fashioned mindset.