The Kli Yakar explains that among many, there are three causes of Tzara’as alluded to in the Torah.
1) The form of Tzara’as called Se’es, which literally means raised, alludes to haughtiness, one cause of Tzara’as.
2) Sapachas - which means secondary - alludes to someone who desires wealth, because of all the things that people desire, wealth is the most secondary, because it is only an ‘add-on’ to a person, and has nothing to do with their intrinsic value.
3) Baheres, which means ‘white spots’ alludes to someone who embarases people, causing their faces to turn white.
Collectively, these afflictions are called צרעת which is a contraction of the words מוציא רע - bringing forth evil. The qualities that bring Tzara’as are bad things that hide in a person, so Hashem punishes them by giving them a specific type of Tzara’as based on their bad trait, showing it off to all.
How should one treat this? The Pasuk answers by instructing one to go to Aharon Hakohen or one of the Kohanim. Aharon and the Kohanim had the opposite of the bad qualities that bring Tzara’as.
1) Aharon and Moshe were together known for their extreme humility, so Aharon was fit to combat Se’es.
2) The Kohanim didn’t get any land in Eretz Yisroel, and therefore they were reliant on the rest of the Jews to give them food and the like. So, they were removed from wanting to be wealthy, allowing them to successfully fight Sapachas.
3) Aharon was known for his love for peace, so much so that he would go to Jews who were fighting and appease them. So, he could combat Baheres.
