Generally, perianal abscesses do not cause weight loss. Typically, perianal abscesses are caused by common bacteria infecting the spaces around the anus and rectum, leading to an acute purulent infection. When an abscess forms, it can cause sudden swelling and pain in the perianal area, with episodic increases in pain. However, if the abscess is caused by tuberculosis bacteria, it can lead to a chronic condition and systemic wasting diseases, which may present symptoms such as night sweats, feverish feelings, etc. Chronic diseases can cause weight loss.