Genetic Mosaicism in an Acquired Inflammatory Dermatosis Following the Lines of Blaschko

Background: Lichen striatus (LS) is a well-known acquired linear inflammatory dermatosis. In 1990, Grosshans and Marot introduced the term ‘adult blaschkitis’ (AB), describing an eruption similar to LS occurring in an adult (adult LS). Does there really exist a new entity or a need for a new naming? Objective and Methods: Two new cases of adult LS are described and the data from 16 earlier cases (12 AB and 4 adult LS) are reviewed. Results: The analysis of 18 adult patients with an acquired inflammatory blaschkolinear eruption reveals that females are affected two times as frequently as males. The mean age at onset is 44 years, the mean duration until spontaneous cure 8.7 months. Relapses occur in 27.7%. In 78%, the eruption is localized on the trunk, in 55% on the arms and in 50% on the legs. Multilinearity is found in 100% if the eruption is on the trunk, and 61.5% if it is on the limbs. Neither clinical nor morphological differences exist between AB and adult LS. Conclusion: There are no convincing characteristics which justify creating a new name or even a new entity. AB may be the same as LS, a well-known acquired linear inflammatory dermatosis, which – as has been shown now – does not occur so rarely in adults. However, the etiology of this entity remains obscure.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Lichen striatus in Adults or ‘Adult Blaschkitis’?

Hofer¹

2003

“…Congenital, nevoid and acquired skin diseases following the Blaschko lines are thought to be caused by genetic mosaicism, resulting from lyonization in X-linked disorders, postzygotic somatic mutations in sporadic conditions and gametic half-chromatid mutations [20]. In 2000, Lipsker et al [21]demonstrated for the first time that also an acquired inflammatory dermatitis in Blaschko-linear distribution shows genetic mosaicism. Another genetic concept, loss of heterozygosity in human skin, plays a role not only in cutaneous malignant growth but also in the development of benign skin disorders [22].…”

Section: Discussionmentioning

confidence: 99%

Meyerson Phenomenon within a Nevus flammeus

Hofer¹

2002

Only few reports about eczematous reactions overlying nevi flammei exist. All of them were observed in children. The description of an eczematous reaction within a congenital nevus flammeus on the left lower leg of a male adult gives reason to discuss this rare phenomenon. Eczema or inflammatory changes within a port-wine stain may mostly be a collision dermatosis with an atopic dermatitis, especially when they arise in children and are localized to the neck and face. When they are observed within a grossly visible vascular malformation, as for example in the Klippel-Trenaunay syndrome, they may have a pathogenesis similar to stasis dermatitis. In rare cases, an eczematous reaction within a nevus flammeus may be the result of genetic mosaicism and is interpreted as a variant of the so-called Meyerson phenomenon.

“…Lipsker et al [26] demonstrated for the first time that an acquired inflammatory dermatosis in Blaschko-linear distribution does show genetic mosaicism. Furthermore various acquired inflammatory eruptions showing linear arrangement are supposed to reflect mosaicism resulting from clonal ‘predisposed’ cells predetermined during embryogenesis [27, 28].…”

Section: Discussionmentioning

confidence: 99%

Does Inflammatory Linear Verrucous Epidermal Nevus Represent a Segmental Type 1/Type 2 Mosaic of Psoriasis?

Hofer¹

2006

Background: A 6-year-old girl with a symmetric linear eruption on both of her legs, clinically and histologically resembling inflammatory linear verrucous epidermal nevus (ILVEN) or linear psoriasis (LP), with concomitant psoriasis of the guttata type and a positive family history of psoriasis is presented. The questions as to whether LP actually exists and ILVEN represents a distinct entity are still under debate. Objective and Methods: The recent literature concerning case reports of ILVEN and LP is reviewed. Results: Case reports of ILVEN and LP can be subdivided into four different groups: (1) ILVEN with or without concomitant psoriasis, only in part reacting to antipsoriatic treatment, (2) ILVEN without concomitant psoriasis, (3) LP with concomitant psoriasis vulgaris, with both groups 2 and 3 reacting successfully to antipsoriatic treatment, and (4) LP without concomitant psoriasis vulgaris and with no family history of psoriasis (very rarely reported). Conclusion: It is hypothesized that inflammatory linear verrucous eruption besides nevoid psoriasis/LP represents a further segmental type 1/type 2 mosaic of psoriasis which, if a (verrucous) epidermal nevus exists, shows a high affinity of occurrence in close context to such a nevus. Heritability is thought to be possible.