It commonly appears on the arms, thighs, and cheeks. Skin contact with allergens or irritants can lead to itchy, raised bumps. Common triggers include detergents, metals, or plants like poison ivy.

Lichen planus is a condition that can cause many different signs and symptoms, including small bumps on the skin, irritated gums, splitting nails, nail loss, itchy bumps on scalp ... on the inside of ...

"They appear as small, red, painful or itchy bumps that can develop pus-filled heads," says the expert. This scalp condition is typically benign, according to research published in StatPearls in 2023.