Pseudoleukoderm L81.5

The term has no consistent history. Lipschütz referred to the non-syphilitic leukoderm as pseudoleukoderm. Others, however, referred to the specific leukoderm as pseudoleukoderm (Renault).

Not uniformly used term for a circumscribed, color contrast phenomenon, whereby light colorations of the skin, which come about in different ways, stand out as a "negative imprint" from normal or darker discolored skin. Pathogenetically (in contrast to vitiligo), there is no reduction in the number of melanocytes, no pathologically reduced melanin content and no dysfunction of the melanocytes. The white colorations in pityriasis versicolor, for example, are not pseudoleukoderma but true leukoderma.

The term "pseudoleukoderma" is also occasionally used for skin colorations whose light color pattern is caused by reduced blood flow, e.g. pseudoleukoderma angiospasticum or naevus anaemicus. Such designations further deepen the conceptual vagueness of "pseudoleukoderma".

• Pseudoleukoderma psoriaticum (e.g. development under cignolin/dithranol therapy-lesional psoriasis foci are not colored by oxidized dithranol, the normal environment turns dark)
• Woronoff rings: Development under dithranol therapy-zonal perilesional light coloration of the skin.
• Mycosis fungoides (sharply defined, light-colored islands of unaffected skin/nappesclaires: pathogenetically unexplained)
• Erythroderma (sharply defined, light-colored islands of unaffected skin/nappesclaires)
• Pityriasis rubra pilaris (sharply defined, light-colored islands of unaffected skin/nappesclaires-diagnostic sign)
• Naevus anaemicus (functional malformation of the capillaries with reduced blood flow and focal skin whitening; negative rubbing test/no redness after rubbing)

• Pseudoleucoderma angiospasticum (vasospastic skin flaking in predisposed individuals (w>m) after exposure to cold or emotional stress) - no leukoderma but a "pale" patch with reduced blood flow.
• Pseudoleukoderma atopicum(pityriasis alba; no leukoderma, as functional deficits of the melanocytes are histologically detectable)
• Naevus anaemicus: no pseudoleukoderm, but merely a pale spot (functional malformation of the capillaries with reduced blood circulation and focal skin whitening; negative rubbing test/no redness after rubbing)

1. Minder E (2012)Drug-induced pseudoleucoderma: a commentary. Acta Derm Venereol 92:220

2. von Bartenwerffer W et al. (2011) Pseudoleucoderma after injections of afamelanotide in a patient with atopic dermatitis. Acta Derm Venereol 91:578-579.