Analysis of 36 cases of Blaschkoid dyspigmentation: reading between the lines of Blaschko

Genetic mosaicism indicated by lines of Blaschko pigmentary changes has been described under a number of different and confusing terms, including hypomelanosis of Ito, linear and whorled nevoid hypermelanosis, nevus depigmentosus, and cutis tricolor. Moreover, extracutaneous findings, particularly serious neurologic defects, have been reported in a large number of these cases. We reviewed the cutaneous and extracutaneous findings in 36 patients referred to the Harriet Lane Pediatric Dermatology Clinic, Johns Hopkins University, from June 12, 2008, to May 24, 2009, for evaluation of macular lesions along the lines of Blaschko. Patients with dyspigmentation along the lines of Blaschko and no history of preceding inflammatory skin lesions were identified for inclusion in a database at their initial visit. Information on age at presentation; sex; age when first diagnosed; type, pattern, and location of the pigmentary anomaly; and extracutaneous abnormalities noted on a review-of-systems questionnaire and physical examination was recorded for each child. Patients were asked to follow up within 6 to 12 months of the initial visit. Patients included 13 boys and 23 girls ages 3 months to 15 years with lesions noted from birth to 12 years. Lesions were hypopigmented in 21 patients and hyperpigmented in 15. No patients presented with hypopigmented and hyperpigmented lesions. Extracutaneous findings were noted in five children (13.9%). Historically, cases of Blaschkoid hypopigmentation and hyperpigmentation have been associated with a high percentage of extracutaneous manifestations, particularly neurologic and neurodevelopmental defects. In our study, only five patients (13.9%) were noted to have extracutaneous abnormalities, and these findings may have been coincidental. We propose the term 'Blaschkoid dyspigmentation' to describe the cutaneous findings. Although serious extracutaneous findings may occur in children with Blaschkoid dyspigmentation and results of careful physical examination and review of systems should direct an evaluation, serious extracutaneous findings occur in a minority of patients.