请输入您要查询的百科知识:

 

词条 Photosensitivity
释义

  1. Skin reactions

      Human medicine    Veterinary medicine  

  2. See also

  3. Notes

  4. External links

{{other uses|photosensitive epilepsy|photophobia|flicker vertigo}}{{Short description|Reaction to incoming photons}}Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity.[1][2] The photosensitive ganglion cells in the mammalian eye are a separate class of light-detecting cells from the photoreceptor cells that function in vision.

Skin reactions

Human medicine

{{main|Photosensitivity in humans}}{{see also|phototoxicity}}

Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn. Particular medications make the skin more sensitive to sunlight; these include most of the tetracycline antibiotics, heart drugs amiodarone, and sulfonamides.

Some dietary supplements, such as St. John's Wort, include photosensitivity as a possible side effect.

Particular conditions lead to increased light sensitivity. Patients with systemic lupus erythematosus experience skin symptoms after sunlight exposure; some types of porphyria are aggravated by sunlight. A rare hereditary condition xeroderma pigmentosum (a defect in DNA repair) is thought to increase the risk of UV-light-exposure-related cancer by increasing photosensitivity.

Veterinary medicine

{{main|Photosensitivity in animals}}

Photosensitivity occurs in multiple species including sheep, bovine, and horses. They are classified as primary if an ingested plant contains a photosensitive substance, like hypericin in St John's wort poisoning and ingestion of biserrula (Biserrula pelecinus)[3] in sheep, or buckwheat plants (green or dried) in horses.[4]

In hepatogenous photosensitization, the photosensitzing substance is phylloerythrin, a normal end-product of chlorophyll metabolism. [5] It accumulates in the body because of liver damage, reacts with UV light on the skin, and leads to free radical formation. These free radicals damage the skin, leading to ulceration, necrosis, and sloughing. Non-pigmented skin is most commonly affected.

See also

  • Bergaptene
  • Heliotropism
  • Photophobia
  • Solar urticaria
  • Snow blindness

Notes

1. ^{{cite book|editor1=Anderson, D.M. |editor2=Keith, J. |editor3=Novac, P. |editor4=Elliott, M.A. |year=1994|title=Dorland's Illustrated Medical Dictionary|edition=28th|publisher=W. B. Saunders Company|isbn=0721655777|translator= }}
2. ^{{cite journal|title=Phototoxicity and photoallergy|author=JH Epstein|year=1999|volume=18|issue=4|pages=274–284|journal=Seminars in Cutaneous Medicine and Surgery|pmid=10604793}}
3. ^Jane C. Quinn; Yuchi Chen; Belinda Hackney; Muhammad Shoaib Tufail; Leslie A. Weston; Panayiotis Loukopoulos (2018), "Acute-onset high-morbidity primary photosensitisation in sheep associated with consumption of the Casbah and Mauro cultivars of the pasture legume biserrula", BMC Veterinary Research, doi:10.1186/s12917-017-1318-7
4. ^buckwheat. Understanding Horse Nutrition.com
5. ^{{cite book |author1=D.C. Blood |author2=J.A. Henderson |author3=O.M. Radostits | title = Veterinary Medicine | publisher = Baillière Tindall | location = London | edition = 5th | year = 1979 | isbn = 0-7020-0718-8 | pages = 841–847 (Lactation Tetany)}}

External links

{{Wiktionary}}
  • Sensor sensitivity (ISO) in digital cameras

2 : Skin physiology|Clinical pharmacology

随便看

 

开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。

 

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间:2024/11/12 15:10:46