Skin Disorders Guide

Diagnostic Hallmarks

1. Distribution: sun-exposed surfaces
2. Fade in winter, darken in summer
3. Size: smaller than 4 mm
4. Occurrence primarily in children

Clinical Presentation

Freckles are light-brown macules 1 to 3 mm in diameter. They occur as closely set, but not confluent, lesions on the lace, arms, and other sun-exposed skin. They occur primarily in fair-skinned people and are particularly prominent in those

of Celtic background. Freckles appear in early childhood and may slowly increase in number thereafter. There is a marked tendency for seasonal variation in color, i.e., darker in the summer and lighter in the winter.

Lentigines and freckles are somewhat similar in clinical appearance but do have different clinical implications.

Course and Prognosis

Freckles are more or less permanent lesions. Gradual fading does occur, however, if continual sunlight stimulation is not malintained. They have no malignant potential, but they do represent an abnormal reaction to sunlight and, as such, should be viewed as a warning sign that further and more scrious sun damage may follow in the years to come. Basically, freckles indicate that the person in question is never going to tan well and that sunlight-protective measures should be taken in an attempt to forestall the development of sun-induced Cutaneous malignancies.

Pathogenesis

Freckles represent the inability of all melanocytes to respond evenly to ultraviolet irradiation. Thus, histologically there is no increase in the number of melanocytes, but individual melanocytes show evidence of increased stimulation. These hyperstimulated cells are more prominent, they are filled with more melanosomes, and their dendritic processes are longer and more numerous.

Therapy

No therapy is necessary. Some bleaching effect can be obtained through long-term application of hydroquinone (Eldoquin Forte, Melanex). However, a reasonable response requires the concomitant, regular use of high sun-protective factor (SPF) sunscreens.