Pierre Louis Alphée Cazenave (5 May 1795 – 9 April 1877) was a French dermatologist who practiced medicine at the Hôpital Saint-Louis in Paris.
In 1823 he was appointed interne to the hospitals of Paris, and in 1835 became professor agrégé to the medical faculty. At Hôpital Saint-Louis, Cazenave was a student of Laurent-Théodore Biett, a physician credited for introducing into French medicine an anatomical approach for analysis of skin disorders. This analytical method was first developed by two English physicians; Robert Willan and Thomas Bateman.
In 1828, with Henri Édouard Schedel, he published a book based on Biett's lectures and observations, titled Abregé pratique des maladies de la peau. The compilation was to become a highly influential dermatological work, being translated into a number of different languages.
From 1844 until 1852, Cazenave was editor of Annales des Maladies de la Peau et de la Syphilis, a journal dedicated to scientific dermatology.
Cazenave is credited with coining the term lupus érythémateux (lupus erythematosus). In 1844 he first described a rare dermatological condition known as pemphigus foliaceus.