Allergology International. 2011;60:401 DOI: 10.2332! allergolint.10-LE-0286
Dear Editor
Superimposed Segmental Dermatomyositis I read with great interest the paper by Takahashi et al. 1 reporting on a child affected by juvenile dermatomyositis (JDM). The peculiarity of the case was the presence of erythema and violaceous papules following a Blaschko’s line over the posterior aspect of the right thigh. The authors speculate that such lesion is an expression of flagellate erythema. However, flagellate erythema of DM is transient, not infiltrated, typically occurs in multiple streaks on the trunk and does not follow Blaschko’s lines. I rather suggest herein that the reported case actually represents a remarkable example of superimposed segmental dermatomyositis. Two types of skin mosaicism are currently recognized with regard to monogenic skin disorders, i. e. type 1 (segments of heterozygous skin in the setting of nonmutant skin) and type 2 (segments of homozygous skin in the setting of heterozygous skin). Segmental manifestations can also be observed in many acquired polygenic skin disorders. In this case, the terms suggested as equivalents of type 1 and type 2 are “isolated” (segmental lesions as the sole manifestation of a dermatosis) and “superimposed” (segmental lesions coexisting with nonsegmental, otherwise typical manifestations of a dermatosis), respectively. 2 Many polygenic skin disorders have been already shown to present, albeit very rarely, with a superimposed segmental manifestation. JDM has been re-
Allergology International Vol 60, No3, 2011 www.jsaweb.jp!
LETTER TO THE EDITOR cently included in the list 3 after the publication of 3 cases featuring segmental calcinosis. 4-6 The case by Takahashi et al. 1 is likely to represent the first reported one in which the segmental manifestation is represented by the pathognomonic findings of DM, i.e. Gottron’s sign and papules. Daniele Torchia1 1 Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA Email:
[email protected] REFERENCES 1. Takahashi Y, Murota H, Tarutani M et al. A case of juvenile dermatomyositis manifesting inflammatory epidermal nevus-like skin lesions: unrecognized cutaneous manifestation of blaschkitis? Allergol Int 2010;59:425-8. 2. Happle R. Superimposed segmental manifestation of polygenic skin disorders. J Am Acad Dermatol 2007;57:690-9. 3. Happle R. Superimposed segmental dermatomyositis: an emerging new paradigm. Eur J Dermatol 2010;20:551. 4. Boente MC, Nadra G, Asial R, Happle R. Pronounced linear calcinosis in a boy with mild dermatomyositis. A further possible example of superimposed segmental manifestation of a polygenic disorder. Dermatology 2009;219: 155-7. 5. Lipsker D, Lenormand C. Classification of polygenic inflammatory diseases distributed along the lines of Blaschko. Dermatology 2009;219:99-101. 6. Fleury J, Guillet G, Anyfantakis V, Huguier V. Unusual calcinosis of muscular loges in a 37 year old patient with a history of juvenile dermatomyositis. Eur J Dermatol 2010; 20:647-8.
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