| 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) |
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| 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) |
| pityriasis rubra | Generalised exfoliation with scaling of the skin and usually with erythema (erythroderma); may be a drug reaction or associated with various benign dermatoses, lupus erythematosus, lymphomas, or of undetermined cause. Synonym: dermatitis exfoliativa, pityriasis rubra, Wilson's disease. (05 Mar 2000) |
| pityriasis rubra pilaris | A chronic skin disease characterised by small follicular papules, disseminated reddish-brown scaly patches, and often, palmoplantar hyperkeratosis. The papules are about the size of a pin and topped by a horny plug. (12 Dec 1998) |
| pityriasis sicca | <dermatology> Dried skin that flakes free from the scalp. (27 Sep 1997) |
| 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) |
| pityroid | Synonym: furfuraceous. Origin: G. Pityrodes, branlike, fr. Pityron, bran, + eidos, resemblance (05 Mar 2000) |
| Pityrosporum | A genus of nonpathogenic fungi found in dandruff and seborrheic dermatitis. Origin: G. Pityron, bran, + sporos, seed (05 Mar 2000) |
| Pityrosporum orbiculare | A fungus species which causes tinea versicolor and which may cause folliculitis. Synonym: Pityrosporum orbiculare. (05 Mar 2000) |
| Pityrosporum ovale | A species of yeast found in superficial epidermal scales and hair follicles on oily skin, of borderline pathogenicity; may cause seborrheic dermatitis associated with immune deficiency. Synonym: Pityrosporum ovale. (05 Mar 2000) |