Darkening on both sides of the bridge of the nose can be caused by UV exposure or clogged pores.
If you have been outdoors for a long period of time without paying attention to sun protection, it is possible to develop darkening on both sides of the bridge of your nose. This is because excessive UV exposure can cause the collagen fibers of the skin to break down, stimulating melanocytes to secrete more melanin and causing darkening on both sides of the nose. To alleviate this, you can apply sunscreen or use a parasol for sun protection.
Darkening of the bridge of the nose can also be caused by sebaceous glands, which block the pores. Darkening on both sides of the bridge of the nose may be more noticeable during seasons of high oil secretion, such as summer. To alleviate this condition, pay attention to the cleanliness of your skin.
There may be other causes of darkening on both sides of the bridge of the nose, and it is advisable to seek prompt medical attention for a definitive diagnosis.