Viral Diseases
Viruses are obligatory intracellular parasites. The structural components of a viral particle (virion) consist of a central core of nucleic acid, a protective protein coat (capsid), and (in certain groups…
Genodermatoses and Congenital Anomalies
The genetic basis for common diseases such as atopic dermatitis and psoriasis, in addition to rare diseases, has been partially elucidated. Some genetic disorders are explained by mutations in a…
Parasitic Infestations, Stings, and Bites
The major groups of animals responsible for bites, stings, and parasitic infections in humans belong to the phyla Arthropoda, Chordata, Cnidaria (formerly Coelenterata), Nemathelminthes, Platyhelminthes, Annelida, and Protozoa. This chapter…
Diseases of the Skin Appendages
Diseases of the Hair Normal human hairs can be classified according to cyclic phases of growth. Anagen hairs are growing hairs; catagen hairs are those undergoing transition from the growing…
Errors in Metabolism
Amyloidosis Amyloid is a material deposited in the skin and other organs that is eosinophilic, homogeneous, and hyaline in appearance. It represents beta-pleated sheet forms of various host-synthesized molecules processed…
Chronic Blistering Dermatoses
In noninherited chronic blistering (vesicular or bullous) dermatoses, the cause of blistering is usually an autoimmune reaction, and the location where antibodies bind determines the clinical, histologic, and immunofluorescent pattern….
Cutaneous Vascular Diseases
Raynaud Phenomenon and Raynaud Disease Raynaud phenomenon is characterized by episodic, recurrent vasospasm of the fingers and toes resulting in white, blue, and red discoloration provoked by cold or stress….
Disturbances of Pigmentation
The visible pigmentation of the skin or hair is a combination of the amount of melanin, type of melanin (eumelanin vs. pheomelanin), degree of vascularity, presence of carotene, and thickness…
Dermatologic Surgery
Dermatology has always been a surgically oriented specialty. Although procedures such as curettage, biopsy, destruction, and excision have been key components of the field, the practice has evolved to include…
Disorders of the Mucous Membranes
Lesions on the mucous membranes may be more difficult to diagnose than lesions on the skin, and not merely because they are less easily and less often seen. There is…
