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The Power of UV

By Maya Schiedel

Ultraviolet (UV) light is known for the harm that it can cause to the human body, most notably skin cancer (“What is skin cancer?”, 2021). Many people are told to stay out of the Sun due to its possible deadly effects. UV exposure can cause sunburn, which is already a sign that your skin is damaged (“What is skin cancer?”, 2021). This damage can build up over time, leading to skin conditions ranging from skin texture to skin cancer (“What is skin cancer?”, 2021). However, many people are also not aware of the positive effects that UV can have, not only in providing our body with the essential vitamin, vitamin D, but also in treating skin conditions (“6 things you should know about vitamin D,” 2020).

Does the term eczema or psoriasis sound familiar? Both are chronic skin conditions that result in itchy, red, inflamed skin (“Eczema,” 2020). They affect millions of people worldwide, and as of now, both do not have an exact cause or cure (“Psoriasis: More than skin deep,” 2019). However, scientists do believe that genetics play a role in psoriasis and eczema, as specific genes can affect the immune system in a way that provokes these conditions (“A deeper look at psoriasis,” 2019). This leaves those affected with constant scratching and red skin, which can be both painful and visually unpleasing (“A deeper look at psoriasis,” 2019). Although there are many medications and treatments for eczema and psoriasis, such as topical creams and ointments, those with more severe skin conditions find that they do not fully alleviate symptoms. This is where UV comes in, through a treatment called phototherapy.

Phototherapy works by using fluorescent UV light on affected areas of the body, as shown above (Barrie, 2021).

Phototherapy works by exposing the skin to UV light (, 2019). The UV light can inhibit an inflammatory response and influence cell division (, 2019). Phototherapy damages skin cells, but this is positive, as it will damage unhealthy skin cells that contribute to eczema or psoriasis (Hopkins, 2015). Specifically, with psoriasis, white blood cells become overactive, which results in excess amounts of cytokines (proteins) being produced (“Psoriasis: More than skin deep,” 2019). This triggers inflammation, which results in the many symptoms of psoriasis (“Psoriasis: More than skin deep,” 2019). By inhibiting an inflammatory response and damaging the cells, this results in reduced cytokines, which means less inflammation. Usually, the skin produces new skin cells in about a month, while with psoriasis, it takes only 3-5 days (“Psoriasis: More than skin deep,” 2019). The scaliness from psoriasis results from keratinocytes (a type of skin cell) that have matured before they are supposed to, due to the speeding up of the skin cell cycle (“Psoriasis: More than skin deep,” 2019). Since phototherapy helps to slow down the growth of these skin cells, the scaliness as well as other psoriasis symptoms will be reduced.

There are many different types of phototherapy, but the most common is narrowband UVB (, 2019). This is because it has a limited UV range of 311 to 313 nanometers (nm), reducing the side effects seen with other types of phototherapy (, 2019). The action spectrum (effectiveness vs. wavelength) for psoriasis has also been determined as 296 to 313nm (Parrish and Jaenicke, 1981), but erythema (sunburn) is dominated under 300 nm (“Understanding Narrowband UVB Phototherapy”). Because of this, the limited range of 311 to 313 nm allows for a safe yet effective treatment of psoriasis and eczema. There are still some risks associated with phototherapy though, including a sunburn-like rash or irritation, hair follicle infections, and more serious and long-term side effects including premature aging/wrinkles as well as an increased risk of skin cancer (, 2019). Another type of phototherapy is psoralen plus Ultraviolet A (UVA), which combines UVA light with a medication that increases sensitivity to the light (, 2019). There are more risks with UVA, so it is not as popular, but it is still effective. Like with many medical treatments, there will inevitably be risks and side effects but the overall benefits are great. Research has shown that phototherapy effectively reduces itching, inflammation, and other symptoms present in both eczema and psoriasis (, 2019).

Make sure to stay protected during phototherapy sessions by wearing sunscreen on the non-affected parts of the body! Also, remember that the dosage and time of phototherapy sessions are based on many factors such as skin tone/type, medical history, etc. which ensures that safety is maximized (, 2019). Scientists and doctors do their best to ensure that your treatments are effective but still safe. If you feel that you are struggling with a skin condition like eczema or psoriasis but none of your medications are working, you can talk to your doctor and see if phototherapy is a good option for you. Phototherapy can be a life-changing treatment, all with the power of UV!


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Barrie, Leslie. (2021, February 17). The Pros and Cons of Eczema Light Therapy.

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_light_reacts_in/ (2019, March 20). Eczema: Light therapy and oral medications.

Parrish, J. A. and Jaenicke K. F. (1981, May 19). Action spectrum for phototherapy of

psoriasis. National Library of Medicine.


Psoriasis: More than skin deep. (2019, June 20). Harvard Health Publishing.


6 things you should know about vitamin D. (2020, October 13). Harvard Health



Understanding narrowband UVB phototherapy. (n.d).


What is skin cancer? (2021, April 28). Centers for Disease Control and Prevention.


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