When people refer to a “monkey bump,” they are using an informal term to describe various skin growths. It is not a medical diagnosis but a colloquial expression for a noticeable lump. Understanding their medical nature can alleviate concerns and guide next steps. This article clarifies the nature of these growths and advises when to seek medical attention.
Understanding the Term “Monkey Bump”
The term “monkey bump” often describes benign skin growths that can appear on different parts of the body. Common types include dermatofibromas, sebaceous cysts (also known as epidermoid cysts), and lipomas. They are generally harmless, though their appearance and texture vary.
Dermatofibromas are firm, round bumps, from 0.5 to 1.5 centimeters in diameter. They are usually found on the arms, lower legs, and upper back and can feel like a small stone beneath or above the skin. While often painless, they can cause itching, irritation, or tenderness at the site.
Sebaceous cysts, or epidermoid cysts, are soft, fluid-filled lumps under the skin. They occur on the face, neck, back, or torso, ranging from pea-sized to larger. They often appear flesh-colored or yellowish with smooth, rounded edges. A central pore may be present, from which a white or yellowish, cheese-like substance can be expressed.
Lipomas are soft, rubbery, fatty lumps that grow slowly between the skin and muscle. They are easily movable with slight finger pressure and are usually painless. While they can form anywhere, they are most often found on the trunk, neck, shoulders, arms, and upper legs. They appear as small knots or lumps below the skin, often matching the surrounding skin color.
Common Causes and Characteristics
Dermatofibromas form after minor skin trauma, such as an insect bite, injury, or ingrown hair. They consist of extra cells (fibroblasts) in the deeper skin layers. They are tethered to the skin surface, causing the overlying skin to dimple inward when pinched.
Sebaceous cysts arise when oil-producing sebaceous glands become blocked or damaged. Blockage leads to a buildup of keratin, a protein found in skin and hair, forming the cyst. Trauma (e.g., scratch, surgical wound) or skin conditions like acne can contribute to their formation. While stable, they can become red, inflamed, and painful if infected.
The cause of lipomas is not fully understood, but genetics play a role; they tend to run in families. They are benign fatty tissue tumors, more common in adults aged 40 to 60. Lipomas feel soft and doughy to the touch. They grow slowly, remaining under 5 centimeters in diameter.
When to Consult a Doctor
While many “monkey bumps” are benign, it is important to know when to seek medical evaluation. Consult a doctor for any new skin lump or if an existing bump changes. A healthcare professional can provide an accurate diagnosis and rule out serious conditions.
Signs warranting a doctor’s visit include rapid growth, changes in color or shape, or if the bump becomes painful. Bleeding, oozing, or signs of infection (redness, warmth, pus) also indicate a need for medical attention. If a lump feels hard, fixed, or has an irregular outline, professional assessment is recommended.