Most swollen glands or lumps under the skin are not cause for concern. The glands (lymph nodes) on either side of the neck, under the jaw, or behind the ears commonly swell when you have a cold or sore throat.

More serious infections may cause the glands to enlarge and become very firm and tender. Glands can also swell and become tender after an injury, such as a cut or bite, or when a tumor or infection occurs in the mouth, head, or neck.

See pictures of swollen lymph nodes and common sites of swollen lymph nodes.

Swollen glands and other lumps under the skin can be caused by many different things, including illness, infection, or another cause:

Infections

Swollen glands commonly develop when the body fights infections from colds, insect bites, or small cuts. More serious infections may cause the glands to enlarge and become firm, hard, or tender. Examples of such infections include:

• Bacterial infections, such as:
  • Strep throat, caused by the streptococcus bacterium.
  • A boil (abscess), similar to a large pimple. A boil may develop when a hair follicle or the skin becomes infected. A sweat gland abscess may form one or more boil-like lumps in the armpit.
• Viral infections, such as:
  • A viral infection of the skin (molluscum contagiosum), which causes small pearly or flesh-colored bumps.
  • Measles, rubella, chickenpox, or mumps.
  • AIDS (acquired immunodeficiency syndrome), which develops in the late stage of HIV (human immunodeficiency virus) infection. This virus attacks the immune system, making it difficult for the body to fight off infection and some diseases.
  • Mononucleosis (Epstein-Barr virus), which also causes fever, sore throat, and fatigue, or cytomegalovirus (CMV), a viral infection that causes symptoms similar to those of mononucleosis.
• Other infections, such as:
  • Lyme disease, an infection that is spread by certain types of ticks.
  • Syphilis, a sexually transmitted disease.

Noncancerous (benign) growths

Types of noncancerous (benign) growths, which are usually harmless, include:

• A lipoma, a smooth, rubbery, dome-shaped lump that is easily movable under the skin.
• A cyst, a sac of fluid and debris that sometimes hurts.
  • Cystic lesions from acne are large pimples that occur deep under the skin.
  • Branchial cleft cysts are found in the neck and do not usually cause problems unless they become infected. These cysts are most common in teenagers.
  • An epidermal cyst (also called a sebaceous cyst) often appears on the scalp, ears, face, and back.
  • A ganglion is a soft, rubbery lump (a type of cyst) on the front or back of the wrist.
• A thyroid nodule, which is an abnormal growth on the thyroid gland, or an enlarged thyroid gland (goiter) in the neck just below the Adam's apple. Tonsillitis may also cause swelling in the neck.
• A salivary gland problem, such as inflammation, a salivary stone, an infection, or a tumor.
• An inflammation of fatty tissue under the skin (erythema nodosum) or overgrown scar tissue (keloid).

Hernias or aneurysms