Casal collar

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Casal collar
PHIL 3757 lores.jpg
A boy with casal collar caused by pellagra
SymptomsRedness and darkening around neck[1]
Differential diagnosisSeborrheic 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]

It is caused by a lack of the vitamin niacin (vitamin B3).[1] Seborrheic dermatitis may appear similar.[1]

The sign is named after Gaspar Casal.[3]

Signs and symptoms


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 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. Archived from the original on 2023-06-30. Retrieved 2023-06-06.
  2. 2.0 2.1 Johnstone, Ronald B. (2017). "4. Psoriasiform reaction pattern". Weedon's Skin Pathology Essentials (2nd ed.). Elsevier. p. 65. ISBN 978-0-7020-6830-0. Archived from the original on 2023-06-30. Retrieved 2023-06-06.
  3. Stedman, Thomas Lathrop (2005). Stedman's Medical Eponyms (2nd ed.). Lippincott Williams & Wilkins. p. 126. ISBN 0-7817-5443-7. Archived from the original on 2023-07-30. Retrieved 2023-07-28.