On human skin, what are often colloquially referred to as "skin barnacles" or simply "barnacle spots" typically appear as light-brown spots that are slightly raised from the skin surface. These growths are medically known as Seborrheic Keratoses, which are common, non-cancerous skin growths that many people develop as they age.
Understanding Seborrheic Keratoses
Seborrheic keratoses are among the most common non-cancerous skin growths in older adults. While their exact cause isn't fully understood, they are often linked to aging, sun exposure, and genetics. They are not contagious and do not pose a health risk, but their appearance can sometimes cause concern or irritation.
Key Characteristics and Appearance
These "skin barnacles" can vary significantly in appearance, but they generally share several distinguishing features:
- Color: They most commonly range from light brown to dark brown or black, but can also be tan, pink, or skin-colored.
- Texture: The surface often looks waxy, scaly, or crusty, and can feel rough. Some might have a velvety texture.
- Elevation: They are typically raised from the skin, appearing as if they are "stuck on" or pasted onto the skin's surface. The degree of elevation can vary from slightly raised to quite prominent.
- Shape: Most are round or oval, though they can sometimes have irregular borders.
- Size: They can range from very small, just a few millimeters, to more than an inch (2.5 cm) across.
Here’s a quick overview of their typical appearance:
| Characteristic | Description |
|---|---|
| Color | Light to dark brown, black, tan, or sometimes pink |
| Texture | Waxy, scaly, crusty, or velvety; often described as feeling "greasy" |
| Elevation | Slightly to distinctly raised, appearing "stuck on" the skin |
| Shape | Generally round or oval, but can be irregular |
| Location | Common on the face, chest, back, shoulders, and scalp |
| Symptoms | Usually painless, but can sometimes itch or become irritated if rubbed by clothing or jewelry |
Common Locations on the Body
Seborrheic keratoses can appear almost anywhere on the body, with the exception of the palms of the hands and soles of the feet. Common areas include:
- Face and Neck: Especially around the temples and forehead.
- Chest and Back: Often appearing as numerous spots, particularly on the upper back.
- Shoulders and Arms: Frequently found on sun-exposed areas.
- Scalp: Can sometimes be hidden by hair.
Development and Variations
The way "skin barnacles" develop and their eventual appearance can vary. They often start as small, rough bumps and gradually grow larger and thicker. Some may remain relatively flat, while others become quite raised and prominent. Over time, their color can darken, and their waxy or crusty texture can become more pronounced. It's common for an individual to develop multiple seborrheic keratoses as they age.
Are These Actual Barnacles?
It's important to clarify that these skin growths have absolutely no relation to marine barnacles, which are crustaceans that attach to rocks, ship hulls, and marine animals. The term "skin barnacles" is purely a descriptive, colloquial term for seborrheic keratoses due to their sometimes rough, raised, and "stuck-on" appearance, reminiscent of actual barnacles.
When to Consult a Dermatologist
While seborrheic keratoses are benign, it's always wise to consult a dermatologist if you notice any new skin growths or if existing ones exhibit concerning changes. Look out for:
- Rapid changes in size, color, or shape.
- Asymmetry, irregular borders, or varied colors within the same growth (the "ABCDEs" of melanoma).
- Bleeding, itching, or soreness that doesn't resolve.
- Any growth that causes pain or discomfort.
A dermatologist can accurately diagnose the growth and rule out more serious conditions like melanoma, which can sometimes resemble a dark, irregular seborrheic keratosis.
