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Evidence Is Conflicting and We Simply Cannot Say

The Essential Info

Researchers have performed over a dozen studies that look at which season is worst for acne. The results of these studies are conflicting, and the answer is not yet definitive.

  • Some studies show acne worsening in the summer
  • Some show acne worsening in the winter
  • Some studies show no seasonal pattern

Sometimes this is how it goes in science. We just have to wait for more evidence to trickle in. Read the full article below if you’re curious about the hypotheses that scientists have put forward for why acne might worsen in the summer or the winter. But keep in mind as you read that nobody knows the real answer to this question.

The Science

Study results on what season tends to coincide with more acne are evenly split across a few possible answers:

  • 5 studies conclude that acne worsens during summer and improves in the winter1-5
  • 5 studies conclude the opposite–that acne worsens during winter and improves in the summer6-10
  • 5 studies conclude that there is no association between seasons and acne11-15

So, as we can see, it’s far too early to confidently confirm any answer to which season is worst for acne.

Expand to read details of studies that show that acne may worsen in the summer
Cutaneous Medicine for the Practitioner

A 1980 study published in Cutaneous Medicine for the Practitioner that examined seasonal differences in acne severity showed that three percent of acne patients’ symptoms worsened during the summer months. The researchers hypothesized that this was likely due to increased sun exposure, although they did not provide a scientific mechanism that would explain this hypothesis.1

The Journal of Dermatology

A 2002 study published in The Journal of Dermatology looked at seasonal variation in 452 acne patients. The researchers found that 56.3% experienced worsening of their acne in the summer, compared to 16.2% seeing improvement in the summer and 11.4% seeing worsening in the winter. Most patients believed that the increased temperature, humidity, and sweating in the summer was behind a summer increase in acne.2

Indian Journal of Dermatology

A 2009 study published in the Indian Journal of Dermatology examined the relationship between acne and seasonal changes in 309 Indian acne patients. The researchers found that 80 patients experienced seasonal worsening of acne, with a large majority of 71 of those patients’ acne worsening during the summer months.3

Dermatology Research and Practice

A 2016 study published in Dermatology Research and Practice examined the prevalence of skin diseases in 23,922 Nepali patients visiting a single hospital. The researchers found that patients reported acne more during the summer season.4

Journal of Cosmetic Dermatology

A 2019 study published in the Journal of Cosmetic Dermatology looked at seasonal variation in acne in India’s tropical climate. The study included 171 patients, 48% of whom reported seasonal variation in their acne. Among the Indian patients who experienced seasonal changes in acne, 84% reported worse acne in the summer.5

Expand to read details of studies that show that acne may worsen in the winter
British Medical Journal

In a 1975 British Medical Journal editorial a doctor proposed that acne would improve during the summer months because UV radiation may improve acne symptoms. However, this proposal was based solely on observations and had not been scientifically examined at the time.6

International Journal of Dermatology

A 2002 study published in the International Journal of Dermatology examined skin diseases of 220 Saudi Arabian patients who visited a dermatologist over the course of a year. The researchers found that acne worsened during winter months but improved during the summer months, with one fifth of all patients visiting the dermatologists reporting acne. However, confounding factors like age prevented the researchers from identifying if the winter season was the sole cause of acne worsening.7

Journal of Dermatology

A 2008 study published in the Journal of Dermatology examined the skin diseases of 6300 Turkish pediatric patients, aged 0 – 16, who were admitted to the hospital between 2004 and 2006. The researchers found that acne was the most common skin disease in these patients. Additionally, the researchers reported that more patients with acne were admitted to the hospital during the winter season.8

Journal of the American Academy of Dermatology

A 2015 study published in the Journal of the American Academy of Dermatology examined the acne severity of 9301 patients in the Northeastern United States for three years to determine if seasonal changes made acne more severe. The researchers found that acne worsened during winter and improved in the summer.9

International Journal of Women's Dermatology

A 2021 study published in the International Journal of Women’s Dermatology looked at how often people in Iran visited a dermatologist for their acne during each season. The researchers found that from 2019 to 2020, 155 patients saw a dermatologist for their acne in the winter, compared to 94 patients in the spring, 109 in the summer, and 98 in the fall. Therefore, the scientists concluded that winter might be the worst season for acne patients. They wrote, “Acne…showed a significant seasonal peak in winter.”10

Expand to read details of studies that show no association between seasons and acne
International Journal of Dermatology

A 1996 study published in the International Journal of Dermatology interviewed 139 patients to determine which season the participants believed worsened their acne. One third of patients reported their acne worsening during winter; one third reported their acne worsening in the summer, and one third reported no worsening during any season.11

Clinics of Dermatology

A 2008 study published in the journal Clinics of Dermatology examined 3931 acne patients to determine if the season in which a patient received acne treatment affected the potency of the treatment. The researchers found retinoid treatments and antibiotics were more effective in clearing acne during the winter months when compared to summer. Although these findings are intriguing, the scientists did not observe any correlation between acne severity and season.12

Journal of Investigative Dermatology

A 2009 study published in the Journal of Investigative Dermatology examined the prevalence of acne in 1002 Iranian high school students. The researchers concluded that there was no correlation between season and acne severity.13

Journal of Drugs in Dermatology

A 2015 study published in the Journal of Drugs in Dermatology examined the skin health of 17 New Jersey adolescents for one year to identify if skin properties like sebum (skin oil) production, moisture content, and acne changed with the seasons. The researchers found that the participants’ skin produced less sebum and decreased in moisture content during winter when compared to other seasons. However, the researchers did not observe any changes in acne severity over the course of the year.14

International Journal of Dermatology

A 2016 study published in the International Journal of Dermatology analyzed the data from 700 patient records from a rural Yemeni health clinic to identify the number and types of skin disorders during the winter months. The researchers found that only eight percent of all skin diseases in these patients involved acne but were not able to determine if the season affected acne severity.15

Study Limitations Make It Hard to Draw a Conclusion

The various studies listed above used participants with different genders, ages, and geographical locations. This variety makes it impossible to effectively compare the research in order to draw conclusions about which season is worst for acne. Therefore, we will need more carefully controlled research with what is called a “standard research population” in order to determine if acne worsens during a particular season.

If acne does in fact get worse in the summer or winter, why might this be so? Let’s start with arguments why acne might worsen during summer and improve during winter.

Why Acne Might Worsen During Summer

Summer tends to bring higher temperatures and increased humidity, so these are the two main suspects. Specifically, scientists speculate that humidity might increase acne by:

  • Bacterial imbalance: Humidity might disturb the balance of bacteria in the skin, allowing acne bacteria to overgrow and making breakouts more likely.
  • A weaker skin barrier: The skin barrier is the outer layer of skin which protects the deeper layers of skin from damage. Some evidence hints that humidity might weaken the barrier, making the skin more prone to breakouts.
  • More sweat: When the air is humid, sweat evaporates more slowly and ends up staying on the skin. Although sweat by itself doesn’t cause acne, if your skin is already physically irritated (such as from rubbing or scratching), sweat can make this worse and potentially trigger more acne.16-19
  • More chance of sunburn: The summer sun can cause sunburn unless the skin is properly protected with sunscreen or clothing. Sunburn is a type of skin irritation, and as the skin heals up from a burn, it often bites back with acne breakouts.

Why Acne Might Improve During Winter

Winter is typically a time of lower air temperatures, lower humidity, and less intense sunshine (although this will depend on your geographical location). Therefore, we might expect the opposite effects on the skin from what we see in the summer:

  • Less bacterial imbalance: A balance of skin bacteria means that acne bacteria don’t have a chance to overgrow.
  • A stronger skin barrier: A healthy skin barrier means the skin is less prone to breakouts.
  • Less sweat: While sweat itself is not an acne trigger, sweat combined with skin irritation can spell more acne. Therefore, less sweating might potentially mean fewer breakouts as well.
  • Less chance of sunburn: As we have seen, a sunburn leaves the skin irritated and susceptible to breakouts, so the less likely a sunburn is, the better for acne-prone skin.

_____

However, as we have seen, some research finds the opposite, that acne might actually worsen in the winter and improve in the summer. Next, let’s look at the arguments why acne might worsen during winter and improve during summer. As you will see, there are still some puzzling inconsistencies.

Why Acne Might Worsen During Winter

  • Skin hydration: To identify what might be the culprit in winter acne, scientists performed four studies between 2014 and 2015 and concluded that it may stem from changes in skin hydration. More specifically, patients in all four studies experienced a decrease in skin hydration during the winter season. Skin hydration is crucial for maintaining the healthy skin barrier, which is important in managing acne.14,20-23
  • A weaker skin barrier: Additional research on the skin barrier function during winter has found one particular component of the skin barrier called ceramides, which can affect acne severity. Ceramides are found within skin cells and support the skin barrier function. Research has identified that acne patients typically possess lower levels of ceramides than patients with healthy skin, and that the levels of ceramides decrease during the winter season. In addition, research has shown that inside clogged pores is an imbalance of ceramides and other fats. This has led scientists to believe that a decrease in ceramides may partly explain the observation that in some people, acne worsens during the winter season.24-29

Arguments Why Acne Might Improve During Summer

Scientists have concluded in four separate studies that the UV radiation from the sun may explain acne clearing in some people during the summer months, specifically by:

  • Decreasing inflammation: Research has shown that UV radiation may act as an anti-inflammatory agent. As inflammation is a major contributing factor to acne development, the researchers believe that UV light may decrease inflammation and help clear acne.
  • Decreased acne bacteria: Additional research has shown that UV light may also help to reduce levels of the bacteria associated with acne called C. acnes.

The combination of anti-inflammatory light and a reduction in C. acnes could explain the observations that acne sometimes clears during the summer season. However, we will need more research to confirm these preliminary findings.1,6,28-31

Conclusion

There is not yet enough evidence to support the idea that acne worsens during a particular season. Scientists will need to perform more rigorous and controlled research before we can conclude anything definitively.

References
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  2. Sardana, K., Sharma, R. C. & Sarkar, R. Seasonal variation in acne vulgaris–myth or reality. J Dermatol. 29, 484‐488 (2002). https://pubmed.ncbi.nlm.nih.gov/12227481/
  3. Adityan, B. & Thappa, D. M. Profile of acne vulgaris–a hospital-based study from South India. Indian J Dermatol Venereol Leprol 75, 272 – 8 (2009). https://www.ncbi.nlm.nih.gov/pubmed/19439880
  4. Poudyal, Y., Ranjit, A., Pathak, S. & Chaudhary, N. Pattern of pediatric dermatoses in a tertiary care hospital of Western Nepal. Dermatol Res Pract 2016 (2016). https://www.ncbi.nlm.nih.gov/pubmed/27247564
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  8. Tamer, E., Ilhan, M. N., Polat, M., Lenk, N. & Alli, N. Prevalence of skin diseases among pediatric patients in Turkey. J Dermatol 35, 413 – 8 (2008). https://www.ncbi.nlm.nih.gov/pubmed/18705828
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