| Casal collar | |
|---|---|
 | |
| A boy with casal collar caused by pellagra | |
| Specialty | Dermatology |
| Symptoms | Redness and darkening around neck[1] |
| Causes | Pellagra[2] |
| Differential diagnosis | Seborrheic dermatitis[1] |
The Casal collar or Casal necklace is a medical sign in which there is a redness and darkening of the skin around the neck, seen in people with pellagra.[2] It becomes prominent following exposure to sun, and can be itchy with a burning feeling and pain.[1] It can blister and weep, and turn into thick dark skin, with a coppery hue.[1] If prolonged, the skin becomes thin, dry and smooth.[1]
The sign is caused by a lack of the vitamin niacin (vitamin B3).[1] Seborrheic dermatitis may appear similar.[1]
Casal collar is named after Gaspar Casal.[3]
- ^ a b c d e f g James, William D.; Elston, Dirk; Treat, James R.; Rosenbach, Misha A.; Neuhaus, Isaac (2020). "22. Nutritional diseases". Andrews' Diseases of the Skin: Clinical Dermatology (13th ed.). Edinburgh: Elsevier. pp. 479–480. ISBN 978-0-323-54753-6.
- ^ a b Johnstone, Ronald B. (2017). "4. Psoriasiform reaction pattern". Weedon's Skin Pathology Essentials (2nd ed.). Elsevier. p. 65. ISBN 978-0-7020-6830-0.
- ^ Stedman, Thomas Lathrop (2005). Stedman's Medical Eponyms (2nd ed.). Lippincott Williams & Wilkins. p. 126. ISBN 0-7817-5443-7.