Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android


The scalp is characterized by a high density of sweat glands and pilosebaceous units consisting of hair follicles, sebaceous glands, and arrector pili muscles. It is estimated that there are some 100,000 follicles on the scalp, so this also means that there are about 100,000 sebaceous glands and associated arrector pili muscles.

Hair on the scalp protects the skin from ultraviolet light and if absent or decreased, predisposes balding individuals to sunburns, photo damage, and photosensitivity. Likewise, the presence of hair may make cleaning the scalp surface with shampoos challenging permitting the development of scalp conditions such as dandruff and seborrheic dermatitis related to colonization of commensal Malassezia yeasts.


Skin diseases involving the scalp can be broadly classified into the following categories (Table 35-1).

  • Inflammatory dermatoses

  • Cicatricial alopecias

  • Infections/infestations

  • Neoplasia

Table 35-1.Skin Diseases of the Scalp.

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.