'Appearance' in the Bible

"When a person has a swelling or a scab in the skin on his body that turns white in appearance and appears to be more extensive than skin deep, he is to be brought to Aaron the priest or to one of his sons among the priests.

The priest is to examine the skin rash on the body. If the hair on the skin rash has turned white and its appearance is deeper than the skin of his body, it's an infectious skin disease. When the priest has examined it, then he is to declare him unclean.

"If the light spot in the skin of his body is white but the appearance of the skin rash isn't deeper than the skin of his body and its hair has not become white, then the priest is to isolate the one who is infected for seven days.

When the priest examines it and finds that the swelling of the skin rash is white or reddish on his bald head or forehead, similar in appearance to an infectious disease in the skin of the body,

Then the priest is to examine it after the contagion has been washed. If the contagion hasn't changed in appearance, even though the contagion hasn't spread, it's unclean. Incinerate it. It's a fungal infection, especially if the infection is on its exposed side.