Topical and Oral Photoprotection for the Treatment of Photodermatoses. A Survey of 90 Dermatologists

Introduction

Photodermatoses are a heterogeneous group of disorders that can be classified as immunologically mediated or idiopathic, drug- or chemical-induced photosensitivity, photoaggravated dermatoses, and photodermatoses associated with defective DNA repair (genetic disorders). Ultraviolet A (UVA) radiation is involved in the pathophysiology of multiple conditions, such as polymorphic light eruption (PLE), cutaneous lupus erythematosus, solar urticaria, actinic prurigo, porphyrias, chronic actinic dermatitis and phototoxic/photoallergic reactions, among others. Their pathophysiology is complex and not fully understood, with ultraviolet B (UVB) radiation and longer wavelengths such as UVA and visible light (VL) frequently involved.^1,2 Management can be challenging, and strict photoprotection together with treatment of the underlying disorder is essential. ³ Although conscientious photoprotection, including the use of broad-spectrum sunscreens (BSSs), is crucial for the management of photodermatoses, ³ we found no studies addressing the type of photoprotection (topical and/or oral) recommended for patients with photodermatoses seen in routine clinical practice.

Most studies on the usefulness of topical photoprotectors in photodermatoses treatment have been conducted on individuals with PLE and have shown a reduction in symptoms of this condition.^2,4–7 Ectoin (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) synthesized by various bacteria, has multiple protective properties, including barrier-stabilizing, hydrating, and cytoprotective effects that may help mitigate UV- and VL-induced cellular damage.^8,9 A topical BSS with Sun protection factor (SPF) >100, UVA protection factor >40, and 1% ectoin (FotoUltra ISDIN Solar Allergy, ISDIN Laboratories, Barcelona, Spain) demonstrated the ability to prevent UVA-induced PLE flares in a randomized study. ²

Polypodium leucotomos (PL) is a fern extract that has been shown in multiple studies to possess antioxidant/anti-inflammatory and photoprotective properties, ¹⁰ and may serve as an adjuvant in the management of photodermatoses such as PLE, solar urticaria, and actinic prurigo.^11–13 PL-containing supplements are considered a form of oral photoprotection and are commercially available in several formulations.

Our objective was to describe the characteristics of both oral and topical photoprotection prescribed for photodermatoses in routine clinical practice, including the prescription and perceived efficacy of a BSS-containing ectoin (BSSE).

Methods

Online survey

An anonymous online survey was conducted among dermatologists from all over Spain who attended a symposium on photoprotection and photodermatoses in May 2023. The survey was carried out as a pretest before the online symposium. It consisted of nine questions (Table 1) about the prescription of topical and oral photoprotection in cases of photodermatoses, and the characteristics of these products. The survey was conducted outside the venue of the symposium, and no commercial products, corporate logos, or marketing elements were displayed. Respondents authorized the management of the data and publication of the results.

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Table 1.

Questions Included in the Survey

1. Among idiopathic or immunologically mediated photodermatoses, indicate how frequently you observe the after conditions in your practice: a. Polymorphic light eruption b. Actinic prurigo c. Solar urticaria d. Chronic actinic dermatitis e. Hydroa vacciniforme

2. Among photoaggravated dermatoses, indicate how frequently you observe the after conditions in your practice: a. Lupus erythematosus b. Dermatomyositis c. Rosacea d. Herpes simplex e. Darier’s disease f. Bullous pemphigoid g. Lichen planus

3. Among drug- or chemical-induced photodermatoses, indicate how frequently you observe the after conditions in your practice: a. Exogenous, phototoxicity b. Exogenous, photoallergy c. Endogenous, porphyrias (cutaneous) d. Endogenous, deficiency (pellagra)

4. How frequently do you usually prescribe photoprotectors as part of the treatment of photodermatoses? a. Always b. Almost always c. Regularly d. Sometimes e. Rarely f. Never

5. When prescribing a photoprotector in these cases, which characteristics are most important for you? (You may select more than one option) a. UVB protection (SPF ≥30) b. Additional ingredients (antioxidants, ectoin, etc.) c. UVB protection (SPF ≥50) d. UVA protection e. Visible light protection f. Cosmetic acceptability for good therapeutic adherence

6. Do you prescribe oral photoprotection with Polypodium leucotomos as part of the treatment of photodermatoses? a. Yes b. No

7. With the combined use of topical and oral photoprotection, have you observed a reduction or disappearance of flares? a. Yes, a reduction in both frequency and severity b. Yes, a reduction in frequency only (not severity) c. Yes, a reduction in severity only (not frequency) d. No reduction or disappearance of symptoms observed

8. As part of the therapeutic management of photodermatoses, have you ever recommended or prescribed the medical device FotoUltra Solar Allergy? a. Yes b. No

9. In those patients for whom you prescribed the medical device FotoUltra Solar Allergy, how would you rate its efficacy in preventing and alleviating symptoms associated with photodermatoses? a. Not effective b. Slightly effective c. Moderately effective d. Effective e. Highly effective

SPF, Sun protection factor; UVA, ultraviolet A; UVB, ultraviolet B.

Results

A total of 90 dermatologists completed the survey (response rate 45.4% [90/198]). The mean age was 40.3 years (SD ± 12.5). Of these, 67.8% (61/90) were women, and 83.3% (75/90) worked in public hospitals (Table 2).

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Table 2.

Epidemiological Characteristics of Respondents

Characteristic	n (%)
Sex
Male	29 (32.2)
Female	61 (67.8)
Total	90 (100)
Age	Mean 40.3 years (SD ± 12.5)
Workplace
Public sector only	42 (46.7)
Private sector only	15 (16.7)
Both	33 (36.6)

N, number; SD, standard deviation.

Types of photodermatoses in clinical practice

Respondents reported that the most frequent idiopathic photodermatosis seen in their practice was PLE (86.7% [78/90]); the most frequent photoaggravated dermatosis was rosacea (76.7% [69/90]); and the most frequent drug- or chemical-induced photodermatosis was phototoxicity (52.2% [47/90]) (Table 3).

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Table 3.

Photodermatoses in Clinical Practice

Characteristic	n (%)
Most frequent idiopathic photodermatosis
Polymorphic light eruption (PLE)	78 (86.7)
Hydroa vacciniforme	0 (0)
Chronic actinic dermatitis	8 (8.9)
Solar urticaria	3 (3.3)
Actinic prurigo	1 (1.1)
Most frequent photoaggravated dermatosis
Lupus erythematosus	9 (10)
Lichen planus	1 (1.1)
Pemphigus vulgaris	0 (0)
Darier’s disease	0 (0)
Herpes simplex	10 (11.1)
Rosacea	69 (76.7)
Dermatomyositis	1 (1.1)
Other	0 (0)
Most frequent drug- or chemical-induced photodermatosis
Exogenous, phototoxicity	47 (52.2)
Exogenous, photoallergy	32 (35.6)
Endogenous, deficiency (pellagra)	1 (1.1)
Endogenous, cutaneous porphyria	10 (11.1)

N, number; PLE, polymorphic light eruption; SD, standard deviation.

Prescription of oral and topical photoprotection for photodermatoses

A total of 98.9% (89/90) of respondents reported prescribing topical photoprotectors always (92.2% [83/90]) or almost always (6.7% [6/90]) to patients with photodermatoses.

In addition, 95.5% (85/89) reported prescribing oral photoprotection with PL as an adjuvant. A total of 97.7% (86/88; 2 nonresponders) observed a reduction in patient symptoms when oral photoprotection was combined with topical photoprotectors, either in both frequency and severity (80.7% [71/88]), in frequency only (6.8% [6/88]), or in severity only (10.2% [9/88]) (Table 4).

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Table 4.

Prescription of Oral or Topical Photoprotection in Patients with Photodermatoses, and Perceived Efficacy

Characteristic	n (%)
Prescription of topical photoprotectors
Never	0 (0)
Almost never	0 (0)
Sometimes	0 (0)
Regularly	1 (1.1)
Almost always	6 (6.7)
Always	83 (92.2)
Prescription of oral photoprotection with Polypodium leucotomos
Yes	85 (95.5)
No	4 (4.5)
Non-responders	1
Symptom reduction with combined use of oral and topical photoprotection
Reduction in both frequency and severity	71 (80.7)
Reduction in frequency only	6 (6.8)
Reduction in severity only	9 (10.2)
No reduction in symptoms	2 (2.3)
Nonresponders	2

Composition of topical photoprotectors prescribed for photodermatoses

Respondents reported that the most important characteristics of sunscreens for photodermatoses were UVA protection (95.6%) (86/90), VL protection (76.7%) (69/90), and the cosmetic properties of the product (67.8%) (61/90). A total of 54.4% (49/90) of dermatologists considered the presence of antioxidants or ectoin in the formulation to be important (Table 5).

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Table 5.

Characteristics Considered Most Important in a Photoprotector for Patients with Photodermatoses

Characteristic	n (%)
SPF ≥30
Yes	8 (9.9)
No	82 (91.1)
SPF ≥50
Yes	19 (21.1)
No	71 (78.9)
UVA protection
Yes	86 (95.6)
No	4 (4.4)
Visible light protection
Yes	69 (76.7)
No	21 (23.3)
Antioxidant ingredients or ectoin
Yes	49 (54.4)
No	41 (45.6)
Adequate cosmetic acceptability
Yes	61 (67.8)
No	29 (32.2)

N, number; SPF, Sun protection factor; UVA, ultraviolet A.

Use of a BSSE in photodermatoses

A total of 90% (81/90) reported regularly prescribing a BSSE to patients with photodermatoses. Of these, 60.7% (54/89; 1 nonresponder) rated it as effective or highly effective in reducing symptoms associated with photodermatoses, while 32.6% (29/89) considered it moderately effective (Table 6).

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Table 6.

Prescription and Estimated Efficacy of a Broad-Spectrum Sunscreen Containing Ectoin in Photodermatoses

Dermatologists	n (%)
Regular prescription of the BSSE
Yes	81 (90)
No	9 (10)
Estimated efficacy of the BSSE
Not effective	2 (2.2)
Slightly effective	4 (4.5)
Moderately effective	29 (32.6)
Effective	47 (52.8)
Highly effective	7 (7.9)
Nonresponders	1

BSSE, broad-spectrum sunscreen containing ectoin.

Discussion

Photodermatoses can severely impact patients’ quality of life and may induce depression or anxiety disorders in a considerable proportion of cases. ¹⁴ PLE is the most frequent photodermatosis, with an estimated prevalence of approximately 20% in Europeans and 10 − 15% in North Americans. ¹⁵ This is consistent with the responses of the dermatologists surveyed in our study. PLE is characterized by a delayed-type hypersensitivity reaction to solar radiation. Its etiopathogenesis appears to involve oxidative stress and destabilization of keratinocyte membrane lipids, processes triggered by UVA radiation. ² PLE is a chronic condition, and a recent study showed that after 20 years of follow-up, more than 70% of patients still had the disease. ¹⁶ This underlines the need for long-term follow-up of these patients and continuous reinforcement of photoprotection measures.

Photoprotection measures such as seeking shade, avoiding sun exposure during peak hours, wearing dark clothing that covers as much skin as possible, and using hats, sunglasses and topical photoprotectors are essential interventions in the management of photodermatoses. ¹⁷ However, studies on the efficacy of topical photoprotectors are limited. Most of the available evidence concerns the management of PLE,^2,4–7 where the deleterious role of UVA radiation is crucial, as discussed above. ¹⁸ In addition, VL has also been implicated in many conditions.^19–21 In our study, we found that most dermatologists considered UVA and VL protection to be the most important features when prescribing a photoprotector for photodermatoses, ranking well above the importance of simply ensuring a SPF ≥50. It is important to recall that physical filters such as titanium dioxide and iron oxides effectively protect against long UVA wavelengths and VL, ²¹ and thus sunscreens containing these filters should be recommended for patients with photodermatoses. Moreover, sunscreens should provide a UVA protection factor greater than one-third of the SPF, ideally approaching a 1:1 ratio. ³

Among the three most frequently cited characteristics considered important in photoprotectors was cosmetic acceptability, with the goal of improving treatment adherence. ²² This is consistent with studies recommending sunscreens with optimal galenic properties: pleasant texture, easy to apply and remove, and leaving no visible residue on the skin. In fact, “cosmetic elegance” was the most frequently cited positive attribute of sunscreens among consumers in one study, ²³ and the most important factor for dermatologists when choosing sunscreens for themselves, according to a recent survey. ²²

PL possesses multiple anti-inflammatory and antioxidant properties that have supported its use in a variety of dermatologic conditions, including pigmentary disorders such as vitiligo and melasma, as well as several photodermatoses.^{11–13,24–27} A recent study showed that supplementation with PL, green tea, and other antioxidants increased the minimal erythema threshold in volunteers. ¹⁰ In our study, almost all dermatologists reported prescribing oral photoprotection with PL for patients with photodermatoses, and most observed a reduction in symptoms when oral photoprotection was combined with topical sunscreens.

The majority of dermatologists in our study also reported regularly prescribing a BSSE and considered it effective in reducing symptoms. In a recent clinical trial, 15 patients with PLE applied this product to a segment of the trunk, leaving another segment untreated. The treated area was then irradiated with UVA (40–60 J/cm²). None of the patients developed PLE lesions in the treated area, whereas 13 of 15 patients developed lesions in the untreated area (p < 0.001). In addition, it effectively protected against UVA-induced erythema and pigmentation. ² Notably, this product exhibits high UVA protection (UVA protection factor > 40) and contains ectoin, an innovative natural molecule that has been shown to protect against Langerhans cell depletion and UV-induced gene expression in keratinocytes. ²⁸ It should be noted that ectoin is not exclusive to a single formulation, and topical photoprotective products containing ectoin are commercially available from different manufacturers.

Limitations and Strengths

This study has several limitations: it was an anonymous online survey, with a potential inclusion bias. Among its strengths, it should be noted that this is the first study to evaluate the prescription of oral photoprotection and topical photoprotectors for photodermatoses in routine dermatological practice, and it included a relatively large number of participants.

Conclusions

The management of photodermatoses can be challenging, and adequate photoprotection is the cornerstone of treatment. Nearly all surveyed dermatologists reported prescribing topical photoprotectors combined with oral photoprotection for photodermatoses and observed a reduction in symptoms with this approach. The most valued characteristics of topical photoprotectors were UVA and VL protection, as well as cosmetic acceptability.