Gary P. Williams, MD

Lines of Blashko may represent normal embryonic movements of the skin during embryogenesis.

This 11-year-old boy has a segmental café au lait macule in a zosteriform distribution. Because the presence of such a lesion may signify somatic mosaicism, a careful review of systems and physical examination of affected patients is indicated. The same cautions apply to patients with large (10-cm) café au lait macules. This patient is vigorously healthy.

McCune-Albright syndrome is classically described as a triad of polyostotic fibrous dysplasia, café au lait macules, and precocious puberty. The syndrome may also be accompanied by various other endocrinopathies including hyperthyroidism, acromegaly, hyperprolactinemia, Cushing syndrome, and hypophosphatemic rickets. Some patients may also exhibit hepatic, cardiac, and GI dysfunction.

This 4-year-old boy has urticaria pigmentosa--one of a group of disorders in which mast cells group together in the skin. Patients may have solitary mastocytomas or (rarely) diffuse infiltration of the skin with mast cells.

This is an autosomal recessive syndrome characterized by chromosomal breakage, pancytopenia, and various congenital abnormalities. It is a heterogeneous condition clinically and has been linked to defects in at least 8 different genes. Fifty percent to 65% of affected persons demonstrate areas of hyper- or hypopigmentation. Café au lait macules, like those shown in Figure A in a 9-year-old boy, are seen in approximately 25% of those affected.

The 12-year-old boy in Figure A has one large and one small café au lait macule and a single hypopigmented macule. Solitary café au lait macules may be present in as many as 30% of newborns. They vary in size from a few millimeters to several centimeters. The macules may be inconspicuous until the affected area is exposed to the sun.

A collage of hyperpigmented macules.

A 6-year-old girl (A) and an 11-year-old boy (B) each presentedfor evaluation of an erythematous, pruritic, papularrash that developed after swimming in a Wisconsin lake.Each child was otherwise completely healthy.

This 10-year-old boy presented forevaluation of a rash that developedduring a spring vacation on Florida’sAtlantic coast. After he had beenswimming in the ocean, a pruritic,erythematous, papular rash developedon his trunk, axillae, and groin. Approximately24 hours after the onsetof the rash, he experienced malaise,chills, and a sore throat. His past medicalhistory was unremarkable. Hehad been fully immunized and hadhad varicella infection.