Losing hair is normal and doesn't make one ritually unclean, but if a bald spot includes a pink discoloration, it might be tzaraas. The kohein will examine him and determine accordingly.

If a person is declared unclean with tzaraas, he must tear his clothes and let his hair grow, like a mourner. He must cover his face and call out "Unclean!" as a warning to others. He'll have to live outside the camp until he heals. (This is "middah k'neged middah," "measure for measure." Since tzaraas is a spiritual punishment for gossip, which separates people, the offender is himself separated from others. See Rashi on 13:46, citing Talmud Arachin 16b.)

Tzaraas could appear on objects other than a person. It could appear on garments of leather, wool or linen. If a bright red or green spot appeared on such an item, it must be shown to a kohein. After examining the garment, the kohein would quarantine it for a week. If the mark increased, it's affected by tzaraas and unclean. Such a garment was unsalvageable and had to be burned.

If the mark did not increase during its week quarantine, the kohein would have it scrubbed and put aside for another week.