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Photochemotherapy
Published in Henry W. Lim, Nicholas A. Soter, Clinical Photomedicine, 2018
Photochemotherapy involves an interaction between nonionizing radiation and a photosensitizing chemical to produce a beneficial effect in disease. In dermatology it applies to the therapeutic use of psoralens and ultraviolet (UV) A radiation, which is referred to by the acronym PUVA. PUVA therapy is used in several forms with variations in the type of psoralen used, the route of administration, and the nature of radiation source, but, unless otherwise qualified, the term will be used here to refer to oral methoxsalen combined with indoor sources of UVA radiation.
Skin
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Zbigniew W. Wojcinski, Lydia Andrews-Jones, Daher Ibrahim Aibo, Rie Kikkawa, Robert Dunstan
PUVA (psoralen + UVA) therapy is a combination of treatment with 8-methoxypsoralen (8-MOP) and UVA (320–400 nm) radiation intended to treat chronic skin diseases such as psoriasis and vitiligo through a photosensitizing mechanism but has been associated with an increased risk of skin cancer. Gavage administration of 8-MOP followed by UVA irradiation for up to 8 months to C3H/HeN-hr hairless mice caused an erythematous phototoxic reaction and scarring but did not result in tumors (Langner et al. 1977). However, PUVA treatment of HRA/Skh mice resulted in a significant increase in hyperplastic skin lesions and cutaneous SCC (Lambertini et al. 2005). Analysis of skin changes in these mice demonstrated increased protein expression of p53 and PCNA (proliferating cell nuclear antigen) in hyperplastic lesions and SCC and an increased mutation frequency of p53 suppressor gene (but not H-ras gene) in SCC. It is proposed that p53 mutation leads to inactivation of p53 protein and subsequent tumor development (Lambertini et al. 2005).
Phototherapy and photochemotherapy
Published in M. Alan Menter, Caitriona Ryan, Psoriasis, 2017
Farhaad R. Riyaz, Henry W. Lim
Ancient Egyptians knew that natural photosensitizing compounds found in vegetables could be combined with exposure to natural sunlight for the successful treatment of vitiligo. Trimethylpsoralen, a synthetically produced psoralen, was first used for the treatment of vitiligo in combination with sunlight. In the 1970s, oral ingestion of 8-methoxypsoralen (8-MOP) combined with high-intensity UVA was shown to be effective for the treatment of psoriasis3; in 1982, this treatment was FDA approved for psoriasis. PUVA has since been used to successfully treat many other inflammatory photoresponsive diseases such as cutaneous T-cell lymphoma, atopic dermatitis, and lichen planus.94
Exploring the potential of nanocarriers in antipsoriatic therapeutics
Published in Journal of Dermatological Treatment, 2022
Mohammad Shaif, Poonam Kushwaha, Shazia Usmani, Supriya Pandey
If the topical procedures fail to work, ultraviolet (UV) radiation may be used to treat the skin. This form of treatment is called phototherapy. By using a fluorescent light source that emits a particular wavelength of radiation, the patient is exposed to UV rays through a special device. Psoriasis is exacerbated by UV rays (25). Regular exposure to UV rays, whether from the sun or artificially, improves symptoms. A combination of UV rays (320–400 nm) and psoralen, commonly referred to as PUVA, improves the skin’s light sensitivity (26). There are other modern methods, such as laser treatment, that emphasize the beneficial effects of light, especially for psoriatic sores. UV light therapy is the most effective and basic treatment for psoriasis (24). Generally, phototherapy is suitable for moderate cases. Usually, systemic treatments are used only in extreme cases or when topical treatments have failed. Conventional systemic therapies include methotrexate (MTX), cyclosporine, and retinoids (27). The systemic methods suppress the immune system and slow the development of skin cells. Dithranol, ammonium glycyrrhizinate, ketoprofen, betamethasone 17-valerate, bortezomib, simvastatin, cyclosporine, retinoids, and other antipsoriatic drugs have all been successfully delivered to the target site through the systemic route (28).
Perspectives on the pharmacological management of psoriasis in pediatric and adolescent patients
Published in Expert Review of Clinical Pharmacology, 2021
Emmanuel Mahé, Maud Amy De La Bretêque, Céline Phan
However, there are two main limitations to using phototherapy in pediatric psoriasis. First, there are concerns over toxicity: these treatments may be associated with an increased risk of skin cancer in adulthood and long-term safety data on their use in pediatric patients is currently lacking. PUVA has also been associated with long-term carcinogenicity, and therefore NBUVB seems to be the safest option for the treatment of childhood cases. In addition, there is the risk of cumulative effects in patients who have used/or are likely to use cyclosporine, another psoriasis treatment with carcinogenic potential. Second, there are issues concerning the feasibility of using phototherapy in young patients. Phototherapy requires patients to attend two or three sessions per week, for a total number of 20 to 30 sessions. Dermatologists and patients in France often find it difficult to maintain this treatment regimen when faced with the demands of other hospital or private practice appointments, and the school-life or extracurricular activities of the patients. As a result, phototherapy is rarely used in children with psoriasis.
Cancer risk in patients with psoriasis: should we be paying more attention?
Published in Expert Review of Clinical Immunology, 2020
Nikolai Dyrberg Loft, Sofie Vaengebjerg, Lone Skov
Ultraviolet (UV) radiation especially narrowband UVB is a well-recognized and effective treatment for psoriasis. Psoralen and UVA (PUVA) have been key in the treatment of moderate-to-severe psoriasis. Skin cancers are the most investigated cancers as a consequence of treatment with UVB and PUVA. Despite UVB is a well-known carcinogen, there is no evidence for UVB treatment and an increased risk of developing skin cancers [94–98] and large prospective studies investigating the carcinogenic effect of specially UVB treatment are lacking [96]. PUVA, on the other hand, confers an increased risk of skin cancer in a dose-dependent manner [99–102], especially for SCC [103]. Additionally, a study reported that PUVA in more than 250 series increased the risk of developing malignant melanoma (MM) [101], and patients who have received more than 200 series have an increased risk of MM compared with those who have received less than 200 (IRR: 2.9, 95% CI: 1.3–6.4) [102]. However, these findings have not been replicated in other prospective studies [67,96,100,104].