How many is too many? A review of the significant numbers in pediatric skin lesions and their recommended evaluation.

Pediatric dermatologists are frequently consulted to evaluate children for cutaneous signs of systemic disorders. Numerical thresholds of significance have been described in the dermatologic literature for various skin findings where the likelihood of an associated extracutaneous abnormality or known genetic syndrome increases significantly. Knowledge of these numerical thresholds facilitates diagnosis and management, which improves clinical outcomes and avoids severe complications. This review highlights the clinical presentation, complications, evaluation, and numerical significance, when applicable, for the following skin findings: infantile hemangiomas, capillary malformations, café-au-lait macules, hypopigmented macules, juvenile xanthogranulomas, pilomatricomas, and angiofibromas.