Does Humid Weather Worsen Acne?
Scientists Speculate That Humidity May Play a Role in Acne Development or the Appearance of Acne on the Skin via Several Mechanisms
Scientists have not performed any research that directly investigates the effect of humidity on acne severity. Therefore, to determine whether it may play a role in acne's worsening, we must rely on studies that investigate the effect of:
- Seasons & acne: Summer is the most humid season
- Altitude & acne: Lower altitudes tend to be more humid
- Geography & acne: Certain places in the world are more humid than others
However, even when we look at these studies, due to a variety of conflicting conclusions, we can't definitively say whether humidity affects acne. This is the case sometimes in science. We must simply say "we don't know" until we get more data. Still, let's have a closer look at the studies we do have and see what we can discover.
Seasons & Acne
Scientists have performed several studies that investigated the relationship between seasons and acne severity. Since summer is normally the most humid season, this could potentially give us a clue into how humidity might factor into acne.
However, many of these studies simply had young people answer surveys. This is called participant self-reporting and is known to be an unreliable scientific method. Some of these studies show very weak evidence that humidity might worsen acne, while others show the opposite or no seasonal changes at all in acne. In other words, based on the evidence we have thus far, the jury is still out on whether acne is worse in particular seasons.
Two independent 2009 studies found that Indian acne patients experienced more acne during the summer season and some participants believed it was due to humidity.1,2
A 2002 study published in The Journal of Dermatology interviewed 452 Indian participants about seasonal changes and acne worsening. The researchers found that the majority of participants reported acne worsening during the summer season. Further, many of the participants believed that the acne exacerbation was due to increased sweating and humidity. However, this study relied solely on participant self-reporting, which is unreliable.3
A 2009 study published in the International Journal of Dermatology interviewed Nigerian high school students regarding their beliefs about what causes acne. Nearly five percent of the participants believed that humidity could exacerbate acne. Although this study shows that some people believe humidity can cause acne, it once again relies on self-reporting and does not provide reliable scientific evidence on how humidity could influence acne.4
Another group of researchers looked at data collected between 2002 and 2016 that analyzed hospital records in Saudi Arabia, Turkey, and Yemen. They found that many patients reported acne during the winter season, when humidity normally decreases.5 - 7
Finally, another set of researchers looked at the data from Iranian acne patients and found no correlation between seasons and acne severity.8 - 10
Altitude & Acne
As altitude increases, humidity tends to decrease. Scientists have performed only two studies, both in 2013, investigating the effect of altitudes on acne. However, one study found that high altitudes might lead to more acne and the other study found the opposite, that high altitudes might lead to less acne.
Expand to read details of studies
A 2013 study published in the Indian Journal of Dermatology investigated the incidence of skin diseases in high altitudes. The researchers found that "low humidity,
A separate 2013 study published in the European Journal of Pediatrics examined the effect of altitude on acne in 6200 boys. They found that boys living in higher altitudes had less acne when compared to boys living in lower altitudes. However, the researchers did not identify if humidity or other factors--including temperature, UV exposure, or wind--contributed to less acne in the boys who lived in higher altitudes.12
Geographical Location & Acne
Researchers have performed several studies to identify if acne prevalence changes depending on where people live. They have also performed studies to see if acne symptoms change during temporary travel to a new area. Overall, researchers have not yet identified if living in certain climates may cause people to be more or less prone to acne. However, some evidence suggests that short-term travel does not affect acne severity.
Living in Certain Geographical Locations
A 2012 study published in the International Journal of Dermatology investigated a skin condition called pityrosporum folliculitis which causes acne-like eruptions on the skin. This study found that pityrosporum folliculitis occurred more often in men but not in women who lived in hot and humid climates. However, it is unclear if the results from studying this condition directly correlate with acne.13
A 2016 study published in the Indian Journal of Dermatology investigated the prevalence of skin diseases in people from a variety of ethnic groups living on a small group of islands east of the Indian mainland. The researchers found that the prevalence of acne and other skin diseases on these islands was similar to that of other hot, humid areas of India.14
Temporary Travel to New Area
A 1983 study published in the Indian Journal of Dermatology investigated whether military personnel were more likely to develop acne when traveling in hot and humid areas. The researchers found that only one solider developed acne after traveling to the new, more humid area. As this is only one case, no conclusions can be drawn regarding traveling and acne.15
A 1997 study published in the Indian Journal of Dermatology, Venereology, and Leprology found that short-term travel to more humid areas did not affect the acne severity of Iranian high school students.9
A 2013 study published in The Nigerian Postgraduate Medical Journal examined the incidence of skin diseases in prison inmates living in a tropical part of Southwest Nigeria that is high in humidity. The researchers found that the tropical environment, stress, and overcrowding of the prison all contributed to the development of skin diseases, including acne. However, the study failed to note if humidity was an important factor in acne development.16
How Humidity Might Make Acne Worse
Although scientists have not yet determined whether humidity levels affect acne severity, they have proposed four mechanisms that may connect humidity with worsening of acne.
1. Microbial Imbalance
Skin health depends on microbes (micro-organisms) and bacteria that support the skin barrier and immune system. These microbes and bacteria also help prevent diseases like acne. When humidity increases, the excess moisture can promote microbial growth and cause an unhealthy imbalance of microbes in the skin, which may exacerbate acne. One 2009 study found that a skin disease called Demodex could worsen in humid environments, so it is hypothesized that the same is true of acne.17,18
2. Oily Skin
When the body temperature rises, the skin secretes more sebum (skin oil) onto the surface of the skin. While this has not been shown to cause acne, a 2012 study discovered that skin oiliness increases in hot and humid environments. However, the observed increase in skin oiliness was not due to a larger amount of sebum, but instead a thinning of the sebum's consistency. This lends credibility to an argument that heat and humidity would result in less acne since acne occurs when sebum becomes trapped inside the pore. However, this is hypothetical, and there is no evidence that the resulting increased sebum excretion from hot and humid weather helps reduce acne.19
3. Impaired Skin Barrier
The skin acts as an important barrier protecting the body from harm. Many skin diseases, including acne, often come with a disrupted barrier. Researchers have proposed that higher humidity may decrease the skin's barrier function. This could increase the severity of acne, but it may also increase the level of permeation of skin medications that can be used to treat acne. Either way, many researchers believe that higher humidity may make the skin more permeable.20, 21
4. Sweat Gland Interactions
Research has shown that sweat remains on the skin longer in a humid environment than a less humid one. This lingering sweat can cause sweat ducts to clog and produce a small red bump on the skin. Although clogging of sweat ducts is not acne, it appears similar to acne.
The Bottom Line
Although scientists have performed numerous studies investigating the effects of seasons, altitude, and geography on humidity and acne, they have not yet identified whether humidity increases acne symptoms. Researchers must perform more reliable, carefully controlled studies investigating this association. In the meantime, scientists have proposed that humidity may worsen acne and/or the appearance of it by disrupting the microbial balance, decreasing the function of the skin barrier, or clogging the sweat glands. However, researchers need to evaluate each of the mechanisms further in order to draw any conclusions on whether or how humidity may affect acne.
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