Selenium disulfide, also known as selenium sulfide, is a chemical compound and medication used to treat seborrheic dermatitis, dandruff, and pityriasis versicolor.[1][2] It is applied to the affected area as a lotion or shampoo.[3] Symptoms frequently return if treatment is stopped.[4]
A 2015 systematic review of topical treatments for seborrheic dermatitis of the scalp identified only a single randomized controlled trial evaluating selenium disulfide for the condition.[15] It was a three-arm trial of 246 people with moderate to severe dandruff and compared treatment with 2% ketoconazole shampoo (n=97), 2.5% selenium disulfide shampoo (n=100), and placebo (shampoo base with no antiseborrheic agent) (n=49) for 29days.[15][16] The study found a 73% reduction in dandruff score with ketoconazole, a 67% reduction with selenium disulfide, and a 45% reduction with placebo.[15][16] Based on the study, the systematic review concluded that selenium disulfide may be effective in the treatment of dandruff but that the available evidence is limited and overall evidence quality is low.[15] It also found that while selenium disulfide has infrequent side effects, it seems to have more side effects than ketoconazole shampoo.[15] Consequently, the review concluded that selenium disulfide should not be considered as a first-line therapy but instead should be used as an alternative treatment after other therapies like ketoconazole shampoo have proven not effective.[15]
A 2015 review recommended topical antifungal agents, topical corticosteroids, and topical calcineurin inhibitors like tacrolimus as the main treatments for seborrheic dermatitis based on good-quality evidence, rather than selenium disulfide for which evidence is much more limited.[17] However, the review did suggest use of over-the-counter selenium disulfide shampoos as an inexpensive option for managing mild symptoms of seborrheic dermatitis.[17]
Selenium disulfide is available in the form of a prescription drug as a 2.25% medical shampoo.[18][19] In the United States, a 1% strength is available over-the-counter, and a 2.5% strength is also available with a prescription.[19] In Canada, the 2.5% strength is available over-the-counter.[19]Selsun Blue is an over-the-counter shampoo for dandruff with 1% selenium disulfide as its active ingredient.[20][19]
Side effects of selenium disulfide shampoo for dandruff appear to be infrequent.[15][16] A randomized controlled trial of 100 people who received selenium disulfide reported side effects of itching or burning sensation of the scalp (3people), eruption near the hairline (1person), psoriasis (1person), lightening or bleaching of hair color (2people), orange staining of the scalp (1person), and a chemical taste while shampooing (1person).[15][16]
Selenium disulfide can cause discoloration of nails and light hair[7] and can alter the color of hair dyes. Several scattered case reports of orange to red–brown scalp discoloration with selenium sulfide shampoo exist.[7][21] The discoloration resolved shortly following discontinuation of selenium disulfide shampoo and its removal could be facilitated by lightly swabbing with isopropyl alcohol.[21] Selenium disulfide may also discolor metallicjewellery. Case reports of temporary diffuse hair loss with selenium disulfide shampoo exist as well.[22][23] Excessive environmental or occupational exposure to selenium has also been associated with hair loss and other adverse effects.[22] However, hair loss has not been reported with topical selenium disulfide in several large studies.[21]
The systemic absorption and toxicity of orally administered selenium sulfide has been studied in animals.[24][7] Topical use of selenium sulfide in the form of a shampoo or lotion in humans does not appear to normally increase circulating or urinary selenium levels.[25][26][27][28][29] However, application of selenium disulfide to damaged skin can result in systemic absorption and has been associated with cases of toxicity.[1] Selenium disulfide appears to be much less toxic than other selenium salts, which may be attributed to its low aqueous solubility and very poor systemic absorption.[7]
Selenium disulfide has a composition that approximates to SeS2 and is sometimes called selenium sulfide. However, as used in proprietary formulations, it is not a pure chemical compound but a mixture of eight-membered-ring compounds where the overall Se:S ratio is 1:2. The specific chemicals contain a variable number of S and Se atoms, SenS8−n.[30]
Many selenium sulfides are known, as indicated by 77Se-NMR spectroscopy.[31]
Selenium sulfide was introduced for medical use in the United States in 1951.[4][19]
Selenium monosulfide, along with elemental selenium and sulfur, has been used in medicinal preparations in the past,[32] causing confusion and contradiction[33] as to exactly what form selenium is in any given topical preparation.
In the film Evolution selenium was mentioned as an active ingredient of Head & Shoulders. A group of academics, therefore, tried to use this brand of shampoo to stop an alien invasion after discovering that the alien life form was sensitive to selenium.[34]
Selenium disulfide has been suggested to be effective as a treatment for hyperkeratosis based on a small case series of three treated patients.[35] It has also been reported to be effective in the treatment of scalp psoriasis based on clinical observation of over 100treated patients and two case reports of dramatic response.[36]
Selenium sulfide is under development for the treatment of meibomianitis (meibomian gland dysfunction) and dry eyes in topical and ophthalmic formulations.[37][38][19] As of March 2021, it is in phase 2/3clinical trials for meibomianitis and phase 2 trials for dry eyes.[37] The developmental code name of selenium sulfide for these uses is AZR-MD-001 and it is being developed by Azura Ophthalmics.[37]
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^"Selenium sulfide". DermNet NZ. New Zealand Dermatological Society Incorporated. Archived from the original on 26 December 2008. Retrieved 24 December 2007.
^Savin R (August 1996). "Diagnosis and treatment of tinea versicolor". The Journal of Family Practice. 43 (2): 127–132. PMID8708621.
^ abcdDanby FW, Maddin WS, Margesson LJ, Rosenthal D (December 1993). "A randomized, double-blind, placebo-controlled trial of ketoconazole 2% shampoo versus selenium sulfide 2.5% shampoo in the treatment of moderate to severe dandruff". Journal of the American Academy of Dermatology. 29 (6): 1008–1012. doi:10.1016/0190-9622(93)70282-x. PMID8245236.
^ abClark GW, Pope SM, Jaboori KA (February 2015). "Diagnosis and treatment of seborrheic dermatitis". American Family Physician. 91 (3): 185–190. PMID25822272.
^"Selenium sulfide shampoo". Bi-Coastal Pharma International LLC. January 2022. Archived from the original on 29 May 2023. Retrieved 29 May 2023 – via DailyMed.
^Rapaport M (1981). "A randomized, controlled clinical trial of four anti-dandruff shampoos". The Journal of International Medical Research. 9 (2): 152–156. doi:10.1177/030006058100900213. PMID7014286. S2CID41649828.
^ abcGilbertson K, Jarrett R, Bayliss SJ, Berk DR (2012). "Scalp discoloration from selenium sulfide shampoo: a case series and review of the literature". Pediatric Dermatology. 29 (1): 84–88. doi:10.1111/j.1525-1470.2011.01410.x. PMID21453309. S2CID42996869.
^Grover RW (April 1956). "Diffuse hair loss associated with selenium (selsun) sulfide shampoo". Journal of the American Medical Association. 160 (16): 1397–1398. doi:10.1001/jama.1956.02960510023006. PMID13306564.
^Henschler D, Kirschner U (1969). "[On the absorption and toxicity of selenium sulfide]" [On the absorption and toxicity of selenium sulfide]. Archiv für Toxikologie (in German). 24 (4): 341–344. doi:10.1007/BF00577584. PMID5795758. S2CID30908076.
^Noisel N, Bouchard M, Carrier G (May 2010). "Disposition kinetics of selenium in healthy volunteers following therapeutic shampoo treatment". Environmental Toxicology and Pharmacology. 29 (3): 252–259. Bibcode:2010EnvTP..29..252N. doi:10.1016/j.etap.2010.02.001. PMID21787610.
^Sánchez JL, Torres VM (August 1984). "Selenium sulfide in tinea versicolor: blood and urine levels". Journal of the American Academy of Dermatology. 11 (2 Pt 1): 238–241. doi:10.1016/s0190-9622(84)70156-3. PMID6480923.
^Slinger WN, Hubbard DM (July 1951). "Treatment of seborrheic dermatitis with a shampoo containing selenium disulfide". A.M.A. Archives of Dermatology and Syphilology. 64 (1): 41–48. doi:10.1001/archderm.1951.01570070044007. PMID14837491.
^Cyclic selenium sulfides R. Steudel, R. Laitinen, Topics in Current Chemistry, (1982), 102, 177-197
^Pekonen P, Hiltunen Y, Laitinen RS, Pakkanen TA (1991). "Chalcogen ring interconversion pathways. 77Se NMR spectroscopic study of the decomposition of 1,2,3,4,5-Se5S2 to 1,2,3,4,5,6-Se6S2 and 1,2,3,4-Se4S2". Inorganic Chemistry. 30 (19): 3679. doi:10.1021/ic00019a022.
Grover RW (April 1956). "Diffuse hair loss associated with selenium (selsun) sulfide shampoo". Journal of the American Medical Association. 160 (16): 1397–1398. doi:10.1001/jama.1956.02960510023006. PMID13306564.
Givens TG, Murray MM, Baker RC (July 1995). "Comparison of 1% and 2.5% selenium sulfide in the treatment of tinea capitis". Archives of Pediatrics & Adolescent Medicine. 149 (7): 808–811. doi:10.1001/archpedi.1995.02170200098016. PMID7795774.
Ransone JW, Scott NM, Knoblock EC (February 1961). "Selenium sulfide intoxication". The New England Journal of Medicine. 264 (8): 384–385. doi:10.1056/NEJM196102232640806. PMID13739506.
Laitinen RS, Pakkanen TA (1987). "77Se NMR spectroscopic characterization of selenium sulfide ring molecules SenS8−n". Inorganic Chemistry. 26 (16): 2598. doi:10.1021/ic00263a010.