ויקרא, פרק י״ג, פסוק מ״ב

When a skin affliction appears on a bald head, the laws of impurity apply much as they do to the rest of the body, yet they carry unique features specific to this location. The head is legally divided into two distinct zones separated by the crown [ברכת אשר]. The back portion slopes from the crown down to the nape of the neck, while the front portion slopes from the crown down to the front hairline [תורה תמימה, אדרת אליהו]. These laws apply equally regardless of how the hair was lost, whether it fell out naturally or was removed through human intervention, such as by consuming or applying hair-removing chemicals [תורה תמימה, אדרת אליהו].

There is a strict legal separation between the front and back of the head. For an affliction to render a person impure, it must be contained entirely within one of these zones. If a mark is split across the boundary of the crown, the two halves do not combine to meet the minimum size requirement. Similarly, if an affliction spreads from the front zone into the back zone, or vice versa, it does not qualify as the type of spreading that causes impurity [רלב״ג, מלבי״ם, תורה תמימה, אדרת אליהו].

The affliction is characterized by a mixed reddish-white color, a shade frequently found on bald spots [מלבי״ם, רד״צ הופמן]. Despite this specific description, any of the standard white shades of impurity apply here just as they do on regular skin [רש״י, רלב״ג, ביאור יש״ר, אדרת אליהו]. This detail also establishes a broader rule that a mixed reddish-white mark is considered impure anywhere on the body [העמק דבר, רלב״ג]. On a deeper level, the presence of red within the white reflects a spiritual imbalance. The red symbolizes strict justice overpowering the white, which represents mercy, indicating the profound severity of the individual's wrongdoing [שפתי כהן].

The criteria for determining impurity on a bald head involve specific signs. The affliction is deemed impure if a patch of healthy flesh appears within it, or if the mark spreads further across the skin. However, the standard sign of hair turning white is entirely excluded here, as the area is already incapable of growing hair [תורה תמימה, מלבי״ם, ביאור יש״ר, אדרת אליהו, רד״צ הופמן]. Ultimately, the affliction itself is not the cause of the initial hair loss. Once the mark heals, the skin simply reverts to its previous pure, bald state, regardless of whether any hair ever grows back [רלב״ג].