- A skin lump or bump covered by normal skin
- Skin swelling just in one spot (localized) is also included
Causes of Skin Lumps
- Insect Bites. The most common cause of an itchy bump is a mosquito bite. Other insects can also cause little bumps.
- Stings. A bee sting can cause a painful bump. The swelling can become quite large.
- Lymph Nodes. Most common cause of a lump or mass felt under the skin. Commonly found in the neck or groin. Nodes have a boundary or edge and are movable. This is not the case for the swelling seen with insect bites. Lymph nodes become larger with infections.
- Scalp Hematoma. The most common cause of a lump on the head is a scalp hematoma (goose egg). In a child under 2 years of age the injury may not have been seen.
- Injuries. New lumps anywhere can be caused by an injury that wasn't observed. A bruise is often present with the swelling.
- Callus. Broken bones heal with new bone formation. The medical term is callus. The callus feels like a bony knot that is larger than the bone itself. A callus is most commonly felt after a collarbone fracture.
- Boils. A boil is a skin abscess. It causes a very painful red lump.
Lumps that are a Normal Part of the Body
- Breast Bud. A small disc-shaped lump felt under the nipple. It indicates the onset of puberty in 7-12 year old girls.
- External Occipital Protuberance. The bony lump felt at the base of the skull in back.
- Mastoid Process. The bony lump felt behind each lower ear.
- Xiphoid Process. A small hard lump felt at the lower end of the sternum (breastbone).
Common Objects Used to Guess the Size
- Pea or pencil eraser: ¼ inch or 6 mm
- Dime: ¾ inch or 1.8 cm
- Quarter: 1 inch or 2.5 cm
- Golf ball: 1 ½ inches or 3.8 cm
- Tennis Ball: 2 ½ inches or 6.4 cm