LeucodermL81.5

Neisser 1885

Circumscribed, acquired, temporary, post-inflammatory hypopigmentation caused by various mechanisms that occur during or as a result of skin diseases or their treatment (intra- and/or perilesional), e.g. pityriasis versicolor, atopic dermatitis , psoriasis vulgaris or infectious exanthema (e.g. syphilis, leprosy, tuberculosis). The size of the depigmentation in leukoderma is generally defined by the preceding lesions.

The term leukoderma is purely morphological and descriptive. It in no way characterizes the nature of the original disease process. If the leucoderm is to be described in more detail, the corresponding adjective (e.g. leucoderma syphiliticum, leucoderma psoriaticum etc.) should be added in each case.

Chemical inhibition of melanogenesis, disturbance in the transport mechanism of melanosomes, UV absorption in scale deposits.

The so-called pseudoleukoderm does not involve disorders of melanocyte function but simple contrast phenomena which occur as in Psseudoleucoderma psoriaticum due to dithranol staining of the surrounding healthy skin.

Diseases that can trigger leucoderma or are associated with it:

• Leucoderma syphiliticum
• Leucoderma leprosum
• Onchocercal dermatitis (shins)
• Leucoderma in pityriasis versicolor alba (confetti-like depigmentation in the seborrhoeic zone)
• Leucoderma in lichen simplex chronicus Vidal
• Leucoderma psoriaticum (see also Pseudoleucoderma psoriaticum spurium - not to be confused with the psoriatic pseudo)
• Leuoderma seborrhoicum (corresponds to areas that previously showed eczematous changes)
• Leucoderma after healed pityriasis rosea (A. Buschke)
• Leucoderma solare (occurring after intensive UV/sun exposure)

• Hypomelanosis guttata (drop-shaped, slightly keratotic leukoderma, especially on the lower extremities)

The opposite of a leukoderma is postinflammatory hyperpigmentation, which can occur in inflammatory dermatoses (e.g. lichen planus) in the case of injuries. Post-inflammatory hyperpigmentation is the hallmark of the fixed drug reaction.