Topical capsaicin. The fire of a 'hot' medicine is reignited.

IMPORTANCE OF THE FIELD: Capsaicin and its receptor, TRPV1, occupy a central place in current neurophysiological studies regarding pain transmission and have opened new avenues for understanding the role of transient receptor potential (TRP) receptors in itch processing. Substantial efforts in drug discovery are at present directed at vanilloid receptors for finding new remedies for pain and itch. AREAS COVERED IN THIS REVIEW: We provide an overview of the major clinical indications of capsaicin, primarily targeting pain and itch of various origins, with an emphasis on the usefulness of capsaicin in treating pruritus and dermatological conditions. In particular, we cover the most relevant findings in recent years, from 2000 onward (although seminal discoveries and studies are discussed irrespective of their date of publication if deemed essential for understanding capsaicin's actions). WHAT THE READER WILL GAIN: Readers are offered a broad perspective on the areas of clinical application of capsaicin, emphasizing its usefulness in the treatment of neurophatic pain and pruritus of various origins. TAKE HOME MESSAGE: Capsaicin has been proven a truly exciting molecule and remains a valuable drug for alleviating pain and itch, widely surpassing its role as a simple spicy ingredient.