The Torah in Parashat Tazria outlines the basic laws of tzara’at skin infections that render a person tamei (ritually impure). This section begins with a discussion of the various forms of tzara’at that surface on a person’s skin, and then addresses the forms of tzara’at that surface in the hair of one’s head and one’s beard (13:29-37). Different guidelines apply when an infection appears in one’s hair, as opposed to the skin. For example, according to most Rishonim (including the Rambam, Hilkhot Tum’at Tzara’at 8:1; Ramban, Vayikra 13:29), the form of tzara’at that surfaces in the hair does not necessarily involve any discoloration. Rather, it manifests itself in the mysterious loss of hair, and the individual is considered tamei if the hairless area spreads, or if a yellow hair grows in the hairless spot. This is in contrast to skin tzara’at, which is a discoloration in the skin that either spreads or changes the color of the hair on the skin to white.
An interesting question arises as to the status of the eyebrows in this regard. Are eyebrows considered the same as the hair on the head and beard, or like the rest of the body?
The Chazon Ish (Taharot, hosafot, p. 296) notes that the Gemara appears to indicate that the eyebrows have the same status as the hair of one’s head and beard with regard to tzara’at. In Masekhet Menachot (37b), the Gemara establishes that although the Torah requires wearing tefillin “bein einekha” (“in between your eyes” – Shemot 13:9 and elsewhere), this actually means that the tefillin should be worn on top of the head, parallel to the area in between the eyes. Rabbi Yehuda, as the Gemara cites, reaches this conclusion by comparing the two tefillin which are worn – the tefillin shel rosh, worn on the head, and the tefillin shel yad, which we wear on our arm. Just as the tefillin shel yad is worn on a place which is susceptible to only one form of tzara’at, Rabbi Yehuda said, the tefillin shel rosh must likewise be worn on a place of the body where only one form of tzara’at applies. If the tefillin would be worn between the eyes, then inevitably, part of the tefillin would be situated on skin, and part would be situated on the hair of the eyebrows. As such, Rabbi Yehuda notes, part of the tefillin would rest on a place where tzara’at is manifest via a white hair (on the skin), and part on a place where tzara’at is manifest via a yellow hair (the eyebrows). Necessarily, then, the phrase “bein einekha” cannot be taken literally, and the tefillin shel rosh is worn on the head, and not in between the eyes.
The clear implication of Rabbi Yehuda’s comment is that the eyebrows are treated like the hair in the head or beard with regard to tzara’at, such that a tzara’at infection is manifest in the eyebrows the same way it is in the hair and beard, and not the way it is on other parts of the body.
However, the Chazon Ish dismisses this conclusion, noting that in no other source is there any mention of the eyebrows being treated like the hair on one’s head and beard with regard to tzara’at. Undoubtedly, the Chazon Ish argues, the eyebrows are no different from other areas of the body where hair naturally grows, regarding which the special laws relevant to the hair of the head and beard do not apply. The Chazon Ish therefore explains the Gemara to mean simply that skin and hair are two separate bodily entities, and tefillin is to be worn on a single entity. The difference between skin and hair noted by the Gemara – that tzara’at is manifest on skin in the form of a white hair, and in hair in the form of a yellow hair – is not a halakhic difference, but rather a factual difference. Meaning, the fact that tzara’at manifests itself one way on skin and another way in hair reflects the fact that they constitute entirely different entities, such that tefillin cannot be worn on both skin and hair. This is not to say, though, that the eyebrows themselves are treated like the hair on the head and the beard.