Melanoma and seborrheic keratosis are two skin disorders that cause the appearance of dark or black spots. Melanoma is a form of skin cancer that is serious and can develop on any area of the body, as stated by the National Cancer Institute. Seborrheic keratosis is a skin growth that is non-cancerous, and it may be mistaken for melanoma, notes Healthline.
Besides melanoma and seborrheic keratosis, there can be many different types of skin growths that may be dark in color, including moles and dysplastic nevi. Although moles and dysplastic nevi are often benign, there is a possibility that they can turn into melanoma, notes the National Cancer Institute.
Melanoma can begin in cells called melanocytes that produce skin pigment. Although these cancerous growths can be different in color, they generally tend to be either brown or black. The main cause of melanoma is overexposure to ultraviolet rays from the sun, as noted by Skin Cancer Foundation. Besides have a dark color, these black spots can present other symptoms that may be warning signs of melanoma, including being asymmetrical, having irregular borders and changing in shape and size over time. Because melanoma can spread to other parts of the body, early detection and treatment of this condition are important.
Seborrheic keratosis is a benign raised growth that can be either brown or black and develop in areas, such as the chest and back. A risk factor for seborrheic keratosis is being age 40 or older.