As summer approaches, our skin faces a new challenge: sun exposure. For healthy skin, dermatologists recommend to avoid prolonged exposure and the use of sunscreens. However, the relationship between sensitive or atopic skin and the sun is a bit more complicated. In this post, we will explain the effect of sun exposure on atopic skin and the importance of proper photoprotection.
Is sun exposure beneficial for atopic skin?
The relationship of sensitive and atopic skin with the sun is complicated since the sun can act as an ally or an enemy to those who suffer atopic dermatitis. Some studies showed that the majority of atopic dermatitis patients benefit from UV radiation therapy or natural sun exposure in a controlled manner1,2.
The mechanism by which ultraviolet therapy is effective in atopic skins is not well understood, but it can be proposed that UVA and UVB radiations may have a local effect on the skin immune system by inhibiting the production of pro-inflammatory mediators. In addition, UV radiation could increase the thickness of the stratum corneum and inhibit the colonization of Staphylococcus aureus in the skin3.
In a systematic review about phototherapy for atopic dermatitis, it was concluded that this therapy could be a valid therapeutic option for patients with atopic skin. However, the reviewed studies have little information available regarding the safety and long-term effects. Moreover, non-serious side effects were reported such as treatment-induced erythema, xerosis, and burning of the skin. Therefore, further well-designed studies are required to assess the long-term effects and benefits of phototherapy and to determine if it is an effective and safe treatment3.
On the other hand, we are sure that exposure to solar UV radiation is recognized as an important factor in the development of several dermatological pathologies that range from skin cancer and actinic keratosis, inflammatory dermatoses and photoaging. Exposure to solar radiation may cause an impaired skin barrier by generating large amounts of free radicals that are harmful to the genetic material in the skin. If you are interested in this topic, visit our post about free radicals and their effect on the skin. Furthermore, prolonged exposure to solar UV radiation generates long-term cumulative damage that has a direct impact on the integrity of proteins and intercellular lipids on the skin barrier4.
The apparent beneficial effect of sunlight in patients with atopic skin is questioned due to its capacity to disrupt the skin barrier. Therefore, it is important to take special photoprotection measures for atopic skin thus limiting the exposure to UV radiation and avoiding the exacerbation of symptoms.
Photoprotection for Atopic Skin
The use of sunscreen products is the basic recommendation for protecting us against the adverse effects of sun exposure. However, people with atopic dermatitis present skin barrier dysfunction and may be at greater risk of allergens penetration. The development of adverse skin reactions to sunscreens can be common in atopic skin patients and therefore choosing a product that works for their skin requires special considerations.
As a general recommendation, sunscreen products for patients with atopic skin should have moisturizing ingredients that can improve the appearance and help restore the skin barrier dysfunction. Moreover, it is important to use broad-spectrum sunscreens that protect the skin against UVA and UVB radiation and with an SPF of 30 or higher.
On the other hand, it is important to consider the type of UV filters used in sunscreen products. Inorganic filters, such as zinc oxide and titanium dioxide, are interesting for atopic skin as they show low rates of sensitization and low allergenic potential. However, these filters may have low consumer acceptability due to the unsatisfactory whitish appearance when they are applied to the skin. As an option, sunscreen products with inorganic filters in a micronized or nanoparticle version can be used as they give the product an almost transparent finish4.
Chemical UV filters tend to have a higher risk of causing allergies and sensitization in atopic skin. Among them, benzophenone-3 (oxybenzone) is the leading allergen and photoallergy. Therefore, dermatologists need to be aware of the adverse effects UV filters might cause in atopic skin and recommend applying a small quantity of the product on the inside of the forearm for a few days to check that the product does not cause a skin reaction4.
If the patient with atopic skin does not have a prior history of sensitization or allergy to chemical UV filters, sunscreen products based on a combination of chemical and inorganic filters can be recommended since these types of products have better sensory attributes and have greater consumer compliance4.
Here you can find some of the features you should take into account when choosing a sunscreen product for atopic skin:
Remember that sun exposure during summer can exacerbate the symptoms of sensitive and atopic skin and therefore it is necessary to use products that offer broad-spectrum protection while also maintaining the hydration levels and restoring the balance of the skin barrier.
REFERENCES
M, N. et al. Impact of sun exposure on adult patients affected by atopic dermatitis. G Ital Dermatol Venereol. (2020). doi:10.23736/S0392-0488.20.06582-7
2. Patrizi, A., Savoia, F., Giacomini, F., Tabanelli, M. & Gurioli, C. The effect of summer holidays and sun exposure on atopic dermatitis. G Ital Dermatol Venereol. 144, (2009).
3. Garritsen, F. M., Brouwer, M. W. D., Limpens, J. & Spuls, P. I. Photo(chemo)therapy in the management of atopic dermatitis: An updated systematic review with implications for practice and research. Br. J. Dermatol. 170, 501–513 (2014).
4. Piquero-Casals, J. et al. The Role of Photoprotection in Optimizing the Treatment of Atopic Dermatitis. Dermatol. Ther. (Heidelb). 11, 315–325 (2021).
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