Lead to the body neck suddenly enlarged, painless, itchy, mainly consider the following aspects of the cause: 1, consider is due to nodular goiter, nodular goiter is a common clinical thyroid disease. Typical performance is diffuse enlargement of the front of the neck, and there is no obvious pain, itching symptoms. Through the thyroid ultrasound examination, it can be found that the thyroid gland is obviously thickened. Through the thyroid function examination, it can determine whether there is hyperthyroidism or hypothyroidism, etc.; 2. Consider that it is due to the rupture and bleeding of the thyroid cystadenoma, which in turn causes the sudden swelling of the neck. Thyroglossal cystadenoma is one of the most common benign diseases of the thyroid gland. If the neck suddenly enlarges due to the enlargement of the adenoma tumor or rupture and bleeding of the tumor, there are usually pain and itching symptoms. If your neck is suddenly enlarged, you need to go to the thyroid surgery department of the hospital in time and have an ultrasound examination of the thyroid gland to make a clear diagnosis. If the enlargement of the thyroid gland is obvious, then surgery is needed to avoid the symptoms of compression, which may cause stuffiness in the front of the neck and hoarseness.