During treatment for TB, what symptom indicates a possible adverse reaction needing immediate attention?

Yellowing of the skin or eyes, known as jaundice, is a significant symptom that can indicate an adverse reaction to tuberculosis medication, particularly with drugs like isoniazid or rifampicin, which can affect liver function. When the liver is damaged or stressed, it may lead to the accumulation of bilirubin in the bloodstream, resulting in the noticeable yellowing of the skin and sclera (the whites of the eyes). This symptom requires immediate medical evaluation and intervention because it may signal hepatotoxicity or other serious complications that could jeopardize the patient's health.

In contrast, increased appetite is typically a positive sign indicating improved health or effectiveness of treatment. Normal fatigue can occur during treatment and does not usually signify an adverse reaction. Minor headaches may be a common side effect of medication but are generally not considered a critical symptom unless accompanied by other alarming signs.