Sunburn: at the beach or in the mountains for a vacation without sunburn

Editorial note

Article originally published in the past and updated according to scientific and informative criteria. The content is for informational purposes only and does not replace the advice of your doctor. For clinical questions or serious cases, consult a healthcare professional.

IN BRIEF

• Sunburn is an inflammatory reaction of the skin due to exposure to ultraviolet rays; it can range from mild redness to burns with blisters.
• Science shows that UV rays damage skin DNA and contribute to the future risk of skin cancer; a history of sunburn is a risk indicator.
• Correct use of effective sunscreens (broad spectrum, adequate amount, reapplication) and other physical measures reduce erythema and long-term lesions.
• Some antioxidant supplements show limited and specific effects in reducing photosensitivity; the evidence does not replace topical protection.
• In acute management, symptomatic measures (cooling, analgesia, emollients) are appropriate; signs of severe burns require medical evaluation.

Abstract: What does science say?

Sunburn is the most common clinical expression of ultraviolet radiation damage. Well-characterized biological mechanisms include DNA photoproduct formation, oxidative stress, and inflammatory response, which produce redness, pain, and, in more severe cases, blisters. Epidemiological evidence links repeated episodes of sunburn to an increased lifetime risk of skin cancers; randomized and observational studies support the effectiveness of regular use of sunscreens and physical measures in reducing skin lesions and some skin neoplasms. Practical effectiveness depends on dose (amount of exposure), frequency (reapplications and duration), and context (e.g., sea, mountains, activities). Antioxidant supplementation shows reduced effects dependent on dose and duration; topical interventions for relief are largely symptomatic. The main limitations concern the heterogeneity of studies, self-reporting of sun exposure, and product variability. [For verified scientific references and DOIs, please refer to the Scientific Research section at the end.]

Why the sun can damage the skin

The energy from ultraviolet (UV) rays interacts with skin tissues, causing direct DNA damage and oxidative reactions in cellular compartments. At the molecular level, photoproducts such as pyrimidine dimers are formed, which interfere with replication and can lead to mutations if not properly repaired [1]. This sequence of events triggers local inflammation: vasodilation, increased temperature, pain, and the production of mediators that sustain redness and itching.

From an epidemiological perspective, a history of repeated sunburns is associated with an increased risk of melanoma and other skin cancers, with effects depending on the age of exposure, skin type, and type of exposure (intermittent vs. chronic) [2][3]. The relationship is probabilistic: the more frequent and severe the burns, the greater the probability of cumulative damage over the years. Therefore, primary prevention aims to reduce acute exposure that causes erythema and to limit the accumulation of damage over time.

How to choose and use sunscreens

Sun protection is a central tool for reducing erythema and long-term damage. An effective product offers broad-spectrum protection (UVB and UVA) and a protection factor suitable for the context and skin type. However, the actual effect depends on the amount applied and correct reapplication: experimental and field studies show that the protection declared in the laboratory can be much higher than the protection achieved in real use if an insufficient amount is used or if it is not reapplied after swimming, sweating, or rubbing [4][5].

In high-risk environments (beach, high altitude), it is reasonable to prefer high-protection filters and water-resistant formulas; for daily activities, screens with sufficient protection combined with physical measures (hat, clothing, shade) are useful. It is crucial to remember that no sunscreen offers complete protection and that usage behavior is decisive for the observed protective effect.

SPF, spectrum, and quantity

The SPF value measures protection against UVB sunburn; UVA protection is evaluated with other indicators and with the "broad spectrum" claim. The expected efficacy from tests refers to the application of a standard quantity (1–2 mg/cm2): in practice, much less tends to be used, substantially decreasing protection. To achieve the indicated SPF, it is important to apply the cream generously to all exposed areas and cover often-forgotten areas (ears, neck, back of hands). The effect of the factor depends on the dose and the continuity of application; under real-use conditions, screens with a higher SPF can still provide additional protection even with reduced applications [5].

When and how to reapply

Reapplication is an essential part of the protective strategy: loss of efficacy can be due to immersion, rubbing, sweating, or simple washing off. A model and experimental studies suggest that a first reapplication performed shortly after the start of exposure can be more effective in reducing overall UV absorption than a delayed reapplication; in practice, the most common operational advice is to reapply every 2–3 hours during prolonged exposure and immediately after activities that remove the product [6].

Role of antioxidant supplements

The literature has evaluated various supplements (beta-carotene, lycopene, vitamin C, vitamin E, zinc, selenium) for their ability to modulate UV-induced skin oxidative stress. Some meta-analyses on beta-carotene and carotenoids have reported a modest reduction in sun sensitivity and sunburn risk under experimental conditions, with effects tending to emerge after repeated and prolonged intake [7].

However, supplements do not replace topical protection: their effectiveness depends on the dose, duration of intake, and the studied population. Furthermore, there are limitations and warnings for certain populations (e.g., smokers for beta-carotene). The evidence therefore suggests that an intake of antioxidants can contribute as general support for skin defense, but it should always be considered a complement to physical protection and sunscreens, not an alternative measure.

Children, phototype, and at-risk groups

Children have thinner skin, and a history of sun exposure in childhood is a factor that increases the cumulative risk of future damage. Pediatric guidelines emphasize the vulnerability of infants and young children and recommend protection through clothing, shade, and prudent use of sunscreens in children over 6–12 months, according to clinical indications [9].

Phototype is an indicator of susceptibility: fair phototypes have less protective melanin and tend to burn more easily; however, darker phototypes can also show cumulative damage. For people with very fair skin or a previous history of sunburn, a more cautious strategy is advisable: physical protection, broad-spectrum filters, and attention to exposure times. Population studies and prevention trials suggest that regular and correct use of sunscreens can reduce certain types of skin lesions in the long term [4].

What to do in case of sunburn

For mild sunburns, management is essentially symptomatic: cool the area (shower or cold compresses), moisturize with non-occlusive emollients, and take analgesics/anti-inflammatories to control pain and local inflammation. Avoid agents that may irritate (e.g., perfumes or products containing benzocaine) and protect the skin until complete healing.

For more intense lesions or those with blisters, fever, or systemic symptoms, medical consultation is necessary. Some topical medications designed for pain and erythema relief, such as low-concentration diclofenac gel, have shown symptomatic reduction in controlled trials when applied in the hours following exposure [8]. These interventions are supportive and do not remove the molecular damage already induced by UV, but they can reduce pain and inflammation in the immediate term.

Finally, pigment regrowth and peeling are common phases of recovery; avoiding new exposures and protecting the skin during re-epithelialization is essential to reduce persistent pigmentary consequences.

KEY POINTS TO REMEMBER

• Erythema is a sign of acute UV damage: limiting its onset is the primary short- and long-term prevention measure.
• Effective protection combines correctly applied sunscreens, protective clothing, and behavior (avoiding the central hours of the day).
• Reapplying sunscreen during prolonged exposure and after swimming or sweating reduces the risk of erythema; timing and quantity are crucial for the actual effect [6].
• Some antioxidant supplements can offer a modest contribution to photoprotection, but they do not replace physical measures and sunscreens [7].
• Children deserve special attention: preventive protection and limiting intense exposures are priorities [9].

Limitations of the Evidence

Available research includes both observational studies and clinical trials: the former measure associations between exposure and risk, while trials test specific interventions. Observational studies can be biased by inaccurate recall of exposure, behavioral differences, and confounding variables (phototype, lifestyle). The strongest causal evidence comes from randomized trials, but in this field, they are relatively few and often limited to specific populations or contexts.

Furthermore, the heterogeneity of products (different commercial formulations), variability in usage behaviors, and environmental differences (latitude, UV index, reflection on water or snow) complicate the interpretation and generalization of results. For these reasons, practical recommendations must be adapted to the individual context and interpreted with caution.

Editorial Conclusion

Sunburn is an evident manifestation of acute skin damage that reflects known and measurable molecular and cellular processes. Preventive strategies with solid efficacy bases combine physical protection, correct use of sunscreens, and behavioral attention. Some nutritional or pharmacological interventions can provide support, but topical protection and limiting exposure remain the cornerstone of prevention. For severe sunburn or systemic symptoms, it is necessary to consult a doctor. This update integrates the main findings from verified scientific literature to help the reader plan holidays and outdoor activities, reducing the risk of sunburn and future skin damage.

Editorial note

This article is an updated version of previously published content. The update was carried out according to criteria of evidence, transparency, and institutional language. The information is for informational purposes only and does not replace medical diagnosis or treatment. For complex or urgent clinical conditions, consult your local healthcare service.

SCIENTIFIC RESEARCH

1. UV-induced DNA damage and repair: a review. Photochemical & Photobiological Sciences. 2002. https://doi.org/10.1039/B201230H [1]
2. Meta-analysis of risk factors for cutaneous melanoma: II. Sun exposure. Eur J Cancer. 2004; https://doi.org/10.1016/j.ejca.2004.10.016 [2]
3. Sunburns and risk of cutaneous melanoma: comprehensive meta-analysis. Ann Epidemiol. 2008; https://doi.org/10.1016/j.annepidem.2008.04.006 [3]
4. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: randomised controlled trial. Lancet. 1999; https://doi.org/10.1016/S0140-6736(98)12168-2 [4]
5. Greater efficacy of SPF 100+ sunscreen compared with SPF 50+ in sunburn prevention: randomized double-blind trial. J Am Acad Dermatol. 2020; https://doi.org/10.1016/j.jaad.2019.09.018 [5]
6. When should sunscreen be reapplied? Diffey BL. Journal of the American Academy of Dermatology. 2001. https://doi.org/10.1067/mjd.2001.117385 [6]
7. Protection from sunburn with beta-carotene: a meta-analysis. Photochemistry and Photobiology. 2007. https://doi.org/10.1111/j.1751-1097.2007.00253.x [7]
8. The efficacy and safety of low-dose diclofenac sodium 0.1% gel for symptomatic relief of superficial natural sunburn: randomized studies. Eur J Dermatol. 2004. https://doi.org/10.1159/000084912 [8]
9. Ultraviolet radiation: a hazard to children and adolescents. American Academy of Pediatrics technical report. Pediatrics. 2010. https://doi.org/10.1542/peds.2010-3501 [9]

For the correspondence between statements in the article and individual research, see the numbers in square brackets corresponding to the citations in the text.