Dermatological findings are often a concern of parents. CAL spots are uniformly hyperpigmented discrete round or oval skin lesions. They are brown in color, with both smooth and irregular borders. The lesions are small in a newborn, increasing in size during childhood, and then become less prominent in adulthood. Histologically, CAL spots have increased melanocytes and melanin in the epidermis.

Children commonly have solitary spots. In the general population, the number and frequency of CAL spots depends on ethnicity and age. In children younger than 10 years of age, the frequency of ≥1 CAL spot has been reported as 13% in white children versus 27% in African American children. When multiple lesions are noted on physical exam, they should raise concern for underlying genetic disorders. Although an evaluation of the child is ongoing, the presence of multiple CAL spots should also prompt investigations of family members.

Neurofibromatosis type 1 (NF1) (Von Recklinghausen disease) is an autosomal dominant disorder (NF1 gene on chromosome 17) and is the genetic disorder most commonly associated with CAL spots. In the general population, NF1 occurs in approximately 1 in 3,500. The CAL spots in NF1 are usually oval-shaped, uniform in color, 1 to 3 cm in diameter, with well-defined borders. The diagnostic criteria for NF1 require two or more physical findings listed in Table 238.1.