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|A boy with casal collar caused by pellagra|
|Symptoms||Rash around neck following sun exposure|
|Differential diagnosis||Seborrheic dermatitis|
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. It becomes prominent following exposure to sun, and can be itchy with a burning feeling and pain. It can blister and weep, and turn into thick dark skin, with a coppery hue. If prolonged, the skin becomes thin, dry and smooth.
It is caused by a lack of the vitamin niacin (vitamin B3). it may appear similar to seborrheic dermatitis.
The sign is named after Gaspar Casal.
Signs and symptoms
- ↑ 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.
- ↑ 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 2021-05-25. Retrieved 2022-04-18.
- ↑ Stedman, Thomas Lathrop (2005). Stedman's Medical Eponyms (2nd ed.). Lippincott Williams & Wilkins. p. 126. ISBN 0-7817-5443-7.