Oculocutaneous albinism (OCA) leads to hypopigmentation of the skin, hair and eyes .1 The most severe phenotype, OCA1, is characterized by the complete lack of melanin production; in subtypes, OCA2, OCA3, and OCA4, some pigment production occurs over the years.2

Actinic keratosis (AK) are premalignant lesions of the skin, commonly located in areas exposed to ultraviolet (UV) radiation.3 OCA patients have an exaggerated sensitivity to UV radiation, which leads the onset of AK lesions and squamous-cell carcinomas, even at young age.

In daylight PDT (DL-PDT), the activation of the photosensitizer protoporphyrin IX (PpIX) from the methylaminolevulinate (MAL) cream by visible light, allows the treatment of AK with less adverse effects of pain and erythema ,4 which favors its use as an alternative to conventional PDT in patients with excessive photosensitivity.5 Other therapeutic options focused on the field of cancerization, such as imiquimod and 5-fluorouracil creams require long-term home treatment regimens and may lead to intense local skin reactions while, ingenol mebutate gel is usually limited to areas of up to 25 cm2 . Thus, the treatment of AK with DL-PDT presents a number of advantages in patients with OCA, in comparison with other treatments.

In 2015, we treated the first patients with OCA at Dona Libânia Dermatology Center in Fortaleza, Brazil. There were three female patients, aged 22, 48 and 65 years old. The use of DL-PDT in patients with OCAs was approved by the local ethics committee.

On the day of the procedure, after the curettage of facial AK lesions, a chemical filter with sun protection factor (SPF) 50 plus lotion (Actinica®, Galderma, France) was applied on the face and other exposed areas. Subsequently, approximately 1 g of of the 16% MAL cream (Metvix®, Galderma, France) was applied throughout the face, and patients stayed outdoors, in the shade, between 7:30 and 9:30 AM. After that, the MAL cream was removed, and patients were discharged, with the instruction to strictly maintain the use of sunscreen at home. AK lesions were counted before the session and after 4, 12 and 24 weeks of follow-up. The patients were also assessed, after 2hours of exposure, for the occurrence and grade of local skin reactions.

A total of 66 facial AK lesions were treated in the three patients, all of whom completed the 24-week period of follow-up. Of the 66 treated lesions, 52 lesions (78.8%) were considered as clinically cured at weeks 4 and 12, and 50 lesions (75.8%) were considered as cured at week 24 (Figures 1 to 3). No pain or burning sensation was reported by any of the patients during the 2-hour shade period. The 22-year-old patient was the only one who presented moderate facial erythema immediate after the procedure, with mild pruritus during outdoor exposure (Figure 4). However, she reported being exposed to the sun for about 10minutes during the 2-hour period with MAL cream. None of the three patients had adverse effects at the 4-week follow-up visit.

Figure 1.

Clinical improvement after 6 months of DL-PDT.

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Figure 2.

Field cancerization of the skin before and 6 months after DL-PDT session.

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Figure 3.

Treatment area before and after 24 weeks of follow up.

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Figure 4.

Moderate facial erythema immediately after the 2-hour outdoor exposition.

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In the current study, we found that nearly 76% of the treated AK lesions could be considered cured after 6 months of follow-up. This cure rate is within the range found in the major European6 and Australian7 muticenter studies of DL-PDT. Since patients with OCA present with extensive AK, with a large number of lesions at an early age, it is important to develop alternative tratments that rapidly eliminate the lesions in large areas and with little local reaction.

During DL-PDT, avoidance of exposure to direct UV radiation through permanence in the shade during the whole period of 2hours is fundamental in patients with OCA. We observed moderate erythema immediately after the procedure in one of the patients, who, despite orientation, was exposed to sunlight for about 10minutes. The city of Fortaleza is located at a low latitude (03°43’02” South), with average annual temperature of 26.3°C. Such warm and sunny weather characteristics allow the use of DL-PDT throughout the year. On the other hand, patients with OCA undergoing DL-PDT in places with similar characteristics have to be carefully instructed about the procedure. Moreover, the use of SPF50 clothing and sunscreen is recommended during the 2-hour exposure in the shade. In our three patients, DL-PDT sessions were scheduled and performed early in the morning, with no overcast or rainy weather.

In conclusion, DL-PDT may be an option in the treatment of multiple lesions of AK on the face of patients with OCA. One of the advantages of treating a wide area such as the face in a single day is the ability to maintain the daily activities of these patients, especially when compared with treatments that require a length of time at home and which may cause skin reactions, both of which can impair adherence to treatment.