In discussing tzara'at which afflicts houses, Vayikra 14:35 describes the start of the procedure to declare the house impure as follows:
וּבָא֙ אֲשֶׁר־ל֣וֹ הַבַּ֔יִת וְהִגִּ֥יד לַכֹּהֵ֖ן לֵאמֹ֑ר כְּנֶ֕גַע נִרְאָ֥ה לִ֖י בַּבָּֽיִת׃
The owner of the house shall come and tell the priest, saying, “Something like a plague has appeared upon my house.”
Nega'im 12:5 picks up on the language of כנגע - something like a plague - and rules:
אֲפִלּוּ תַלְמִיד חָכָם וְיוֹדֵעַ שֶׁהוּא נֶגַע וַדַּאי, לֹא יִגְזֹר וְיֹאמַר נֶגַע נִרְאָה לִי בַּבָּיִת, אֶלָּא כְּנֶגַע נִרְאָה לִי בַּבָּיִת.
Even if he is a learned sage and knows that it is definitely a nega, he may not speak with certainty saying, "A plague has appeared upon my house," but rather, "Something like a plague has appeared upon my house."
Does this rule apply to other types of tzara'at (e.g. on the body or on clothing) as well?
If yes, why is it mentioned in the Torah and Mishnah specifically with respect to house-tzara'at? If no, what is the rationale for it to apply only to house-tzara'at?