Puzzling Purpuras: Tale of an Unusual Bruise

An otherwise healthy 7-year-old boy has an odd "rash" on one ankle. The pediatric hematologist has ruled out a number of malignancies and bleeding disorders. The parents are very anxious to find out what's wrong. And now they bring him to you.In these slides, follow Dr Jonathan Schneider's typically cautious, consistently thorough process to puzzle out the cause of the unusual bruise.

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Recommended reading

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►Magro CM, Schaefer JT, Crowson AN, Li J, Morrison C. Pigmented purpuric dermatosis: classification by phenotypic and molecular profiles. Am J Clin Pathol. 2007;128:218-229.

►Zvulunov A, Avinoach I, Hatskelzon L, et al. Pigmented purpuric dermatosis (Schamberg's purpura) in an infant.  Dermatol Online J. 1999;5:2.

►Nagata K, Danno K, Tanaka S, Unilateral Schamberg disease in a 14-year-old Japanese boy. J Dermatol. 1999;26:348-351.

►Lasocki AL, Kelly RI. Narrowband UVB therapy as an effective treatment for Schamberg's disease. Australas J Dermatol. 2008;49:16-8 http://onlinelibrary.wiley.com/doi/10.1111/j.1440-0960.2007.00411.x/abstract

►Aiba S, Tagami H. Immunohistologic studies in Schamberg's disease. Evidence for cellular immune reaction in lesional skin. Arch Dermatol. 1988;124:1058–62. doi: 10.1001/archderm.124.7.1058.

►Newton RC, Raimer SS. Pigmented purpuric eruptions. Dermatol Clin. 1985;3:165-9. http://www.ncbi.nlm.nih.gov/pubmed/4092379

►Abeck D, Gross GE, Kuwert C, et al. Acetaminophen-induced progressive pigmentary purpura (Schamberg's disease).  J Am Acad Dermatol, 1992;27:123-4

►Baselga E, Drolet BA, Esterly NB. Purpura in infants and children.  J Am Acad Dermatol. 997;37:673-705 http://www.ncbi.nlm.nih.gov/pubmed/?term=J+Am+Acade+Dermatol.+997%3B37%3A673-705