Hard lumps in the skin can be caused by common infections of the skin, usually due to bacterial infections that form localized inflammation, for example, like folliculitis or inflammation of the soft tissues of the skin, and so on. In addition to this, there is another kind of hard lumps formed by allergies, which is usually seen as urticaria, that is, acute urticaria or chronic urticaria, which is usually the skin surface of the wind, and this kind of wind is pressed or touched, and there is the feeling of hard lumps. In addition to hives, of course, there is also the possibility of psoriasis, and usually plaque psoriasis is also a manifestation of hard skin.