Freckles (Ephelides)

Freckles are the most common hyperpigmented macules seen in childhood. They are light to dark brown in color, smaller than 3 mm in diameter, irregular in contour, and found on sun-exposed areas such as the face, upper back and chest, and dorsal surface of the arms. They are not present at birth and develop over childhood. They are found most often in individuals with red hair and fair skin. The typical pattern is for freckles to increase in number and prominence in the summer and fade in the winter. The development of excessive freckling may suggest an underlying photosensitivity, as seen in xeroderma pigmentosum. Although benign in nature, individuals with lighter pigmented skin who are predisposed to the development of freckles are at higher risk of developing malignant melanoma.

Lentigines

Lentigines are round, brown to black macules, 4 to 10 mm in diameter that increase in number during adolescence and, at times, can be almost indistinguishable from ephelides. Clinically, lentigines occur anywhere on the body, not just in sun-exposed areas, and do not fade in the winter. Lentigines are quite common and benign when few in number. However, when multiple, lentigines constitute the primary clinical feature of a number of syndromes. The most important syndromes with lentigines as a defining feature are LEOPARD (lentigines, electrocardiogram abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and deafness) syndrome, also known as multiple lentiginous syndrome, Peutz-Jeghers syndrome, and Carney’s complex (Figure 124-1 and Table 124-1). The clinician evaluating a patient with innumerable lentigines on examination should keep the above diagnoses in mind, especially if lentigines are noted on mucosal surfaces or cross the vermillion border because these are not features of benign lentiginosis.

Figure 124-1 Lentigines.

Table 124-1 Major Lentiginous Syndromes

Café-au-Lait Spots

Café-au-lait spots (CALS) are one of the most common hyperpigmented lesions, with one or two CALS present in approximately 25% of school-age children. Although CALS may be noted at birth, many CALS develop in early infancy and may increase in size and number throughout childhood. They are sharply defined, round to oval in shape, and light brown and homogenous in color and can range from 2 mm to more than 20 cm in diameter. CALS occur anywhere on the body but are generally located on the trunk and lower extremities, sparing the face and upper extremities. Similar to lentigines, CALS are benign in nature but may signal an underlying systemic disease.

The two most common disorders in which CALS are the principal cutaneous feature and may be the primary clinical finding at the time of diagnosis are neurofibromatosis type I (NF1) and McCune-Albright syndrome. The CALS seen in NF1 are multiple and have a smooth circumference often compared to the “coast of California” (Figure 124-2). The number or distribution of CALS is not associated with the severity of disease in NF1. Other principal cutaneous findings in NF1 are described in Table 124-2. Although one or two CALS are quite common, fewer than 1% of children younger than 5 years of age have more than five CALS without having NF1 or the newly described Legius’ syndrome. Recent literature suggests that many patients previously labeled as having mild NF-1 in fact have an “NF-like syndrome” termed Legius’ syndrome, resulting from the autosomal dominant inheritance of a mutation in the SPRED-1 gene. Legius’ syndrome is characterized by multiple CALS, skin fold freckling, and an increased risk of macrocephaly and learning disabilities but without the other distinguishing features of NF-1 (see Chapter 76 for diagnostic criteria for NF-1). The CAL of McCune-Albright syndrome tends to be unilateral and large, stops abruptly at the midline, creating a segmental appearance, and has a jagged border likened to the “coast of Maine” (see Figure 124-2). Other associated features of McCune-Albright syndrome include precocious puberty and polyostotic fibrous dysplasia, although many children with large segmental café-au-lait macules have no associated syndrome. The clinician should consider the number and size of CALS along with other salient features by examination and history to guide their workup.

Figure 124-2 Café-au-lait spots.