| pityriasis versicolor | A common chronic, noninflammatory and usually symptomless disorder, characterised by the occurrence of multiple macular patches of all sizes and shapes, and varying in pigmentation from fawn-coloured to brown. It is seen most frequently in hot, humid, tropical regions, and is caused by pityrosporon orbiculare. (12 Dec 1998) |
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| versicolor | Variegated; marked by a variety of colour. Origin: L. Particolored, fr. Verso, to turn, twist, + colour, colour (05 Mar 2000) |
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| membrana versicolor | 1. <cell biology> Layer of reflective tissue just behind the pigmented retinal epithelium of many vertebrate eyes. May consist either of a layer of guanine crystals or a layer of connective tissue. In bovine eyes reflects a blue green iridescent colour. 2. <plant biology> Layer of cells in the sporangium of a vascular plant that nourishes the developing spores. (18 Nov 1997) |
| Ipomoea versicolor | A species whose seeds contain hallucinogenic ergot (indole) alkaloids. (05 Mar 2000) |
| tinea versicolor | A common chronic, noninflammatory and usually symptomless disorder, characterised by the occurrence of multiple macular patches of all sizes and shapes, and varying in pigmentation from fawn-coloured to brown. It is seen most frequently in hot, humid, tropical regions, and is caused by pityrosporon orbiculare. (12 Dec 1998) |
| trichonosus versicolor | A rare condition in which the hair shows alternate pigmented and bright segments, the latter due to air cavities within the cortex. Synonym: leukotrichia annularis, pili annulati, thrix annulata, trichonosus versicolor. (05 Mar 2000) |
| pityriasis | <dermatology> A name originally applied to a group of skin diseases characterised by the formation of fine, branny scales, but now used only with a modifier. Origin: Gr. Pityron = bran (18 Nov 1997) |
| pityriasis amiantacea | An inflammatory condition of the scalp in which heavy scales extend onto the hairs and bind the proximal portions together; it is not caused by a fungus. Synonym: pityriasis amiantacea. (05 Mar 2000) |
| pityriasis capitis | <dermatology> Dried skin that flakes free from the scalp. (27 Sep 1997) |
| pityriasis circinata | A mild exanthematous inflammation of unknown aetiology. It is characterised by the presence of salmon-coloured maculopapular lesions. The most striking feature is the arrangement of the lesions such that the long axis is parallel to the lines of cleavage. The eruptions are usually generalised, affecting chiefly the trunk, and the course is often self-limiting. (12 Dec 1998) |
| pityriasis lichenoides | A subgroup of parapsoriasis itself divided into acute and chronic forms. The acute form is characterised by the abrupt onset of a generalised, reddish-brown, maculopapular eruption. Lesions may be vesicular, haemorrhagic, crusted, or necrotic. Histologically the disease is characterised by epidermal necrolysis. The chronic form shows milder skin changes with necrosis. An important variant of the chronic form is lymphomatoid papulosis. (12 Dec 1998) |
| pityriasis lichenoides chronica | An eruption lasting up to a few years, of reddish-brown papules with central scaling, that clears without scarring. Origin: Lichenoides Mod. L., fr. G. Leichen, lichen, a lichen-like eruption, + eidos, resemblance chronica Mod. L. Chronic, fr. G. Chronikos, pertaining to time; fr. Chronos, time (05 Mar 2000) |
| pityriasis linguae | <clinical sign> A benign condition where there is a map-like appearance to the tongue resulting from irregular denuded patches in the surface (loss of tongue papillae). Likely secondary to local irritation from hot or spicy foods, alcohol or tobacco. There are no significant complications. (27 Sep 1997) |
| pityriasis maculata | A mild exanthematous inflammation of unknown aetiology. It is characterised by the presence of salmon-coloured maculopapular lesions. The most striking feature is the arrangement of the lesions such that the long axis is parallel to the lines of cleavage. The eruptions are usually generalised, affecting chiefly the trunk, and the course is often self-limiting. (12 Dec 1998) |
| pityriasis nigra | A fungus infection due to Exophiala werneckii, marked by dark lesions giving a spattered appearance and occurring most commonly on the palms of the hands. Synonym: pityriasis nigra. (05 Mar 2000) |
| pityriasis rosea | A mild exanthematous inflammation of unknown aetiology. It is characterised by the presence of salmon-coloured maculopapular lesions. The most striking feature is the arrangement of the lesions such that the long axis is parallel to the lines of cleavage. The eruptions are usually generalised, affecting chiefly the trunk, and the course is often self-limiting. (12 Dec 1998) |