Freckles

Ephelides: small, tan to light brown macules on sun exposed skin, which darken with ultraviolet exposure and fade in winter. They are not caused by an increase in melanocytes. The melanocyte count is normal, and the epidermal melanin is increased.

• Inheritance is autosomal dominant. They are strongly associated with variants of the melanocortin 1 receptor gene (MC1R), red or fair hair, blue or green eyes, and pale skin (skin types I and II).
• They appear after sun exposure from the age of 2 to 3 years, increase through childhood, and fade in adult life.
• They are markers for sun sensitivity and carry a higher risk of melanoma, basal cell carcinoma and squamous cell carcinoma, because of the underlying skin type and the MC1R variants, not because freckles themselves are premalignant.
• They differ from lentigines (which persist in winter and have more melanocytes).

• Multiple 1 to 3 mm (up to 5 mm) well defined round or oval, uniformly tan, red brown or light brown macules, with a regular border, on the face (cheeks, nose, forehead), shoulders, upper back, and arms.
• Colour intensifies after sunlight and fades with sun avoidance. They are asymptomatic.
• Features suggesting a syndrome or another condition:
  • Axillary or inguinal freckling with six or more café-au-lait macules and neurofibromas (neurofibromatosis type 1).
  • Perioral, lip and buccal mucosa pigmented macules in a child, with abdominal pain or bleeding (Peutz-Jeghers syndrome).
  • Marked freckling in a child with severe sunburn, ocular photophobia, and early skin cancers (xeroderma pigmentosum).
  • Lentigines with cardiac, endocrine or myxoma features (LEOPARD syndrome, Carney complex).
• Differential diagnosis: solar and simple lentigines, junctional naevi, café-au-lait macules, lentigo maligna, melasma, post-inflammatory hyperpigmentation and drug pigmentation.
• Complications: none from the freckles themselves. The skin type carries an increased risk of burning and skin cancer.

• Clinical. Check that all lesions are uniform, small, symmetrical in colour, and sun related.
• Full skin examination and dermoscopy. Biopsy any lesion that is atypical, rapidly growing, irregular in colour, larger than 6 mm, or inconsistent with its neighbours.
• If a genetic syndrome is suspected, arrange referral for clinical genetics, with testing for NF1, STK11, PRKAR1A and the xeroderma pigmentosum genes as indicated.
• Record skin type, burn history, number of naevi, and family history of melanoma.

• No treatment is required. Explain that freckles are benign and a marker of sun sensitivity.
• Photoprotection (the most important measure):
  • Broad spectrum sunscreen SPF 50, applied thickly (2 mg/cm2) 20 minutes before exposure and reapplied every 2 hours, and after swimming or sweating.
  • Shade, wide brimmed hat, UV-protective sunglasses, tightly woven clothing, avoidance of 10 a.m. to 4 p.m. sun, and no sunbeds.
  • For children, make sun protection a routine from infancy. Keep infants under 6 months out of direct sun.
• Skin surveillance: teach monthly self-examination using the pattern of "asymmetry, border irregularity, colour variation, diameter above 6 mm, and evolution", and arrange an annual full skin examination for those with many naevi, a family history of melanoma, or a history of blistering sunburn.
• Vitamin D: strict sun protection may reduce vitamin D synthesis, so consider supplementation 800 to 1000 IU (20 to 25 micrograms) daily in at risk patients with low levels (older people, those with covered skin, limited diet).
• Cosmetic treatment on request (effect is temporary because freckles return on sun exposure):
  • Tretinoin 0.025 to 0.05% cream nightly, increasing as tolerated, for 3 to 6 months.
  • Hydroquinone 2 to 4% cream twice daily for 2 to 3 months, then stop.
  • Vitamin C (L-ascorbic acid 10 to 20%) serum, and azelaic acid 15 to 20% twice daily.
  • Superficial peels (glycolic acid 30 to 50%) or intense pulsed light, or Q-switched 532 nm or 755 nm lasers for individual lesions. Test a patch first, and avoid sun for 4 to 6 weeks.
  • Liquid nitrogen cryotherapy, 2 to 3 seconds, for isolated lesions, with a risk of hypopigmentation.
• Special groups:
  • Pregnancy: sunscreen only. Avoid retinoids, hydroquinone, peels and lasers.
  • Children: protection and education, with no cosmetic treatment.
  • Xeroderma pigmentosum: strict ultraviolet avoidance, specialist care and lifelong surveillance.
• Follow up: annual skin check for those at high risk. Refer to dermatology for any changing or suspicious lesion, for suspected syndrome, or for laser treatment.