Sebaceous adenitis is an autoimmune disease that affects sebaceous glands. The stratified squamous epithelium gradually accumulates sebaceous and apocrine glands. These are usually attributable to overactive sebaceous glands, which produce excess sebum. Retinoids reduce the amount of sebum produced by the sebaceous glands. Sebaceous and apocrine glands become active at puberty. Scent glands and sebaceous glands are often present. Sebaceous glands secrete acids that form the acid mantle. The increased production of sebum can lead to a blockage of the sebaceous gland duct. The drug decreases the size and sebum output of the sebaceous glands. The sacs are lined with apocrine and sebaceous glands. Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucous. Warthogs have two facial glands&colon; the tusk gland and the sebaceous gland. It may also be secreted by human sebaceous glands. In the skin CFTR is strongly expressed in the sebaceous and eccrine sweat glands. It reduces the size and secretion of the sebaceous glands.