Sunspots (Solar Lentigines) - Western SummaryWestern Medicine Summary

Western Medicine

Western Summary

Sunspots are dark spots that occur in areas of the body that have been sun-exposed such as the face, arms, legs, and back. They are not dangerous medically but many people want them removed for cosmetic reasons. 

Symptoms

Sunspots, also known as solar lentigines, appear as brown flat lesions occurring in sun-exposed areas such as the face, arms, hands, and shoulders. They tend to develop more often in those with Fitzpatrick skin types III or IV[1] although people of other skin types can develop them. 

Causes

Sunspots form when the pigment producing cells in the skin (melanocytes) become overactive. Triggers that stimulate melanocytes to become overactive include exposure to sunlight and ultraviolet light[2] as well as pollution.[3] 

Treatments

Treatments are aimed at reducing the appearance of the sunspots by using the following approaches: 

  • Reduce pigment production: The enzyme that controls pigment production in melanocytes is tyrosinase. Therefore, tyrosinase inhibitors can be used to reduce pigment production. Examples of tyrosinase inhibitors include hydroquinone, kojic acid, and azelaic acid. 
  • Increase turnover of the cells that have pigment: Once the melanocytes make pigment, they share that pigment with surrounding cells in the skin that are known as keratinocytes. Some treatments are aimed at helping these cells turnover more quickly so that they are replaced in the skin. Examples include tretinoin and retinol. 
  • Sun protection: Broad-spectrum sunscreens are important to reduce stimulation of pigment production in the melanocytes. Both ultraviolet light type A and type B must be blocked. Look for sunscreen ingredients that have broad blockade power including avobenzone, ecamsule, zinc oxide, titanium dioxide, and iron oxide. 
  • Physical destruction of the pigment: Lasers can be targeted toward unwanted pigment to selectively reduce the pigment containing cells and the melanocytes.
  • Direct removal of the pigment producing cells: Chemical peels can help remove cells that contain too much pigment.

 

1.    Monestier S, Gaudy C, Gouvernet J, et al. Multiple senile lentigos of the face, a skin ageing pattern resulting from a life excess of intermittent sun exposure in dark-skinned caucasians: a case-control study. Br J Dermatol.2006;154(3):438-444; PMID: 16445772.

2.    Idorn LW, Datta P, Heydenreich J, et al. Black light visualized solar lentigines on the shoulders and upper back are associated with objectively measured UVR exposure and cutaneous malignant melanoma. Photochem Photobiol Sci.2015;14(2):481-487; PMID: 25410723.

3.    Huls A, Vierkotter A, Gao W, et al. Traffic-Related Air Pollution Contributes to Development of Facial Lentigines: Further Epidemiological Evidence from Caucasians and Asians. J Invest Dermatol.2016;136(5):1053-1056; PMID: 26868871.