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Ochronosis is the syndrome caused by the accumulation of homogentisic acid in connective tissues. The phenomenon was first described by Rudolf Virchow in 1865.〔Findlay GH, et al. Ochronosis. Clinics in Dermatology 1989;7:28-35〕 The condition was named after the yellowish (ocher-like) discoloration of the tissue seen on microscopic examination. However, macroscopically the affected tissues appear bluish grey because of a light scattering phenomenon known as the Tyndall effect. The condition is most often associated with alkaptonuria but can occur from exogenous administration of phenol complexes like hydroquinone. == Exogenous ochronosis == There are two types of ochronosis: endogenous and exogenous. The endogenous variety is an autosomal recessive disease, that is caused by a lack of homogentisic oxidase enyme.〔Charlín, R., Barcaui, C. B., Kac, B. K., Soares, D. B., Rabello-Fonseca, R. and Azulay-Abulafia, L. (2008), Hydroquinone-induced exogenous ochronosis: a report of four cases and usefulness of dermoscopy. International Journal of Dermatology, 47: 19–23. 〕 Exogenous ochronosis is an avoidable dermatitis, that can be caused by the topical application of compounds such as hydroquinone or phenols.〔 It was first seen in 1912, when a patient who used phenol on a leg ulcer was found to have this condition by Beddard and Plumtre.〔Beddard AP, Plumtre CM. A further note on ochronosis associated with carboluria. Q S Med 1912; 5: 505–507.〕 Hydroquinone induced exogenous ochronosis was found by Findlay in 1975, who observed the condition in patients who used skin lightening creams containing the compound.〔FINDLAY, G., MORRISON, J. and SIMSON, I. (1975), Exogenous ochronosis and pigmented colloid milium from hydroquinone bleaching creams. British Journal of Dermatology, 93: 613–622. 〕 There are three clinical stages of exogenous ochronosis:〔Dogliotte M, Leibowitz M. Granulomatous ochronosis – a cosmetic- induced skin disorder in blacks. S Afr Med J 1979; 56: 757–760.〕 # erythema and mild hyperpigmentation # hypergimentation and ‘’caviar-like’’ lesions # papulo-nodular lesions 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ochronosis」の詳細全文を読む スポンサード リンク
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