Thyroid nodules are not an infectious disease and are generally not contagious. Thyroid nodules can be caused by pathological reasons such as overgrowth of thyroid tissue, chronic inflammation of the thyroid gland, or induced by factors such as heredity, iodine deficiency and ionizing radiation. Most thyroid nodules are benign adenomatous nodules or cysts, which are usually asymptomatic and do not require therapeutic intervention if there is no significant change in the shape or size of the nodule after diagnosis. A small percentage of thyroid nodules are malignant tumors, or require prompt surgical removal when the nodule is large enough to compress the surrounding tissues and cause hoarseness, dyspnea, or dysphagia. If thyroid nodules are suspected, it is recommended to go to the hospital for ultrasonography and fine needle aspiration cytology for diagnosis and treatment under the guidance of a doctor.