My grandpa has these dark waxy bumps on his neck that itch. What are they?

While the exact cause of seborrheic keratoses is not entirely understood, certain factors are believed to contribute to their development. Sun exposure over many years is thought to play a role, as these growths often appear on sun-exposed areas of the skin. Genetics also significantly influence their formation, as they tend to run in families. Additionally, irritation from clothing or other factors can exacerbate the itchiness and discomfort associated with these growths.

While seborrheic keratoses are usually harmless, there are instances when medical advice should be sought. If a growth starts to itch excessively, bleed, or change in size, shape, or color, it is important to consult a dermatologist. These changes could potentially indicate a different condition that requires attention. Persistent symptoms, such as severe itching or bleeding, should not be ignored as they can lead to secondary infections or other complications.