Scalp diseases are common in both children and adults. They can occur as primary scalp diseases, such as tinea capitis, traction alopecia, folliculitis keloidalis nuchae, and folliculitis decalvans, or as part of a generalised skin disease, like atopic dermatitis, seborrhoeic dermatitis, psoriasis, lichen planus, pityriasis rubra pilaris, and secondary syphilis. Scalp disorders can be non-scarring and reversible, while others can cause scarring, and are often permanent.