Sun, in moderation is good for us but overexposure to the sun’s rays can cause both short and long-term damage to all skin types including oily skin. You can read more about the positive and negative effects of sun on skin in How do UVA, UVB and HEVIS light rays affect skin?
Excessive and/or unprotected exposure to the sun’s rays can exacerbate the causes and triggers of acne making matters worse rather than better:
- The sun causes skin to dry out and even oily skin needs moisture. When skin dries out the sebaceous glands go into overdrive and this excessive sebum production is one of the key stages in the formation of blemishes.
- When skin dries out its surface hardens. This interferes with the natural process whereby dead skin cells are shed and so pores block and blemishes develop.
- The sun also leads to increased sweat production and speeds up the rate at which sweat degrades on skin’s surface. This creates the perfect environment for the bacteria associated with acne to spread.
Sunlight can also trigger a particular type of acne known as Acne Aestivalis (more commonly known as Mallorca Acne). Acne Aestivalis occurs when UVA rays combine with the chemicals in certain skincare and sun protection products and trigger an allergic reaction. It typically effects women between 25 and 40 who experienced acne during puberty and you can read more about it in the different types of acne.
People with acne marks (pigmentation issues caused by Post Inflammatory Hyperpigmentation or PIH) are particularly prone to further issues of hyperpigmentation. Excessive sun exposure and/or inappropriate sun protection can exacerbate acne-related hyperpigmentation.
Certain acne treatments and medications − e.g. Benzoyl Peroxide, Tretinoin, Adapalene and Azelaic Acid − also make skin more susceptible to sun damage and increase the need for appropriate sun protection. You can find out more in acne and medication.
You can read more about this subject in Does sun help acne or make it worse?