The medical name is acrochordon. They are harmless and do not become cancerous or malignant. The precise cause is unknown. Skin tags do not need treatment. If skin tags become sore from rubbing clothing or jewelry or if you find them unsightly, they can be removed surgically.
Healing is usually complete in a week or two.
New skin tags may form even if all existing tags are removed. Some people have their skin tags disappear if they take chromium picolinate 200 mcg twice a day. This trace element is available at health food and drug stores without a prescription. Chromium polynicotinate can also be taken and is sold under the name Natrol ChromeMate . This mineral must be taken for 3 months to see the results and if you stop taking the chromium the tags will recur.