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(medicine) the act of caring for someone (as by medication or remedial training etc.); "the quarterback is undergoing treatment for a knee injury"; "he tried every treatment the doctors suggested"; "heat therapy gave the best relief"

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(病気の)治療,療法 / =psychotherapy

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/22 12:46:12」(JST)

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PUVA is an ultraviolet light therapy treatment for eczema, psoriasis, graft-versus-host disease, vitiligo, mycosis fungoides, large-plaque parapsoriasis and cutaneous T-cell lymphoma using the sensitizing effects of the drug psoralen.^[1]^:686^[2]^[3] The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA.

Photodynamic therapy is the general use of nontoxic light-sensitive compounds that are exposed selectively to light, whereupon they become toxic to targeted malignant and other diseased cells. Still, PUVA therapy is often classified as a separate technique from photodynamic therapy.^[4]^[5]

Procedure

Psoralens are photosensitizing agents found in plants. Psoralens are taken systemically or can be applied directly to the skin. The psoralens allow a relatively lower dose of UVA to be used. When they are combined with exposure to UVA in PUVA, they are highly effective at clearing psoriasis and vitiligo. Like UVB light treatments, the reason remains unclear, though investigators speculate there may be similar effects on cell turnover and the skin's immune response.

Choosing the proper dose for PUVA is similar to the procedure followed with UVB. The physician can choose a dose based on the patient's skin type. The dose will increase in every treatment until the skin starts to respond.

Some clinics test the skin before the treatments, by exposing a small area of the patient's skin to UVA, after ingestion of psoralen. The dose of UVA that produces uniform redness 72 hours later, called the minimum phototoxic dose (MPD), becomes the starting dose for treatment.

At the very least for vitiligo, narrowband ultraviolet B (UVB) phototherapy is now used more commonly than PUVA since it does not require the use of the Psoralen. As with PUVA, treatment is carried out twice weekly in a clinic or every day at home, and there is no need to use psoralen.^[6]

Narrowband UVB does not cure the legs and hands, compared to the face and neck. To the hands and legs PUVA may be more effective. The reason can be because UVA penetrates deeper in the skin, and the melanocytes in the skin of the hands and legs is deeper in the skin. The Narrowband UVB does not reach the melanocytes.

Side effects and complications

Some patients experience nausea and itching after ingesting the psoralen compound. For these patients PUVA bath therapy may be a good option.

Long term use of PUVA therapy has been associated with higher rates of skin cancer.^[7]

The most significant complication of PUVA therapy for psoriasis is squamous cell skin cancer. Two carcinogenic components of the therapy include the nonionizing radiation of UVA light as well as the psoralen intercalation with DNA. Both processes negatively contribute to genome instability.

History

Psoralens have been known at least since ancient Egypt. In the 1890s Niels Ryberg Finsen of Copenhagen developed a bulky phototherapy machine to treat skin diseases using UV light. In 1900, French electrical engineer, Gustave Trouvé miniaturized Finsen’s machine with a series of portable light radiators to heal skin diseases such as lupus and epithelioma. Such machines have only been available in a chemically synthesized form since the 1970s.^[8]

References

^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
^ Domínguez MA, Membrillo VG, Ramos GA (2004). "Large plaque parapsoriasis and PUVA-therapy. A case report".
^ MacMillan Cancer Support Group. "Cutaneous T-cell lymphoma (CTCL)".
^ Finlan, L. E.; Kernohan, N. M.; Thomson, G.; Beattie, P. E.; Hupp, T. R.; Ibbotson, S. H. (2005). "Differential effects of 5-aminolaevulinic acid photodynamic therapy and psoralen + ultraviolet a therapy on p53 phosphorylation in normal human skin in vivo". British Journal of Dermatology 153 (5): 1001–1010. doi:10.1111/j.1365-2133.2005.06922.x. PMID 16225614.
^ Champva Policy Manual, Chapter: 2, Section: 30.11, Title: PDT (Photodynamic Therapy) and PUVA (Photochemotherapy) at U.S. Department of Veterans Affairs. Date: 12/23/2011
^ What are the treatment options for vitiligo?
^ Melissa Conrad Stöppler, MD. "Psoriasis PUVA Treatment Can Increase Melanoma Risk".
^ Gustave Trouvé French Electrical Genius (1839–1902)" - McFarland Books - Author: Kevin Desmond pp. 162-164

External links

Phototherapy Course, New Zealand Dermatological Society
PUVA Therapy Description at Oxsoralen-Ultra Indications

Light Therapy for Dermatologic Conditions at Blue Cross and Blue Shield Association of North Carolina

UpToDate Contents

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1. ソラレン・紫外線A（PUVA）光化学療法 psoralen plus ultraviolet a puva photochemotherapy
2. Treatment of psoriasis
3. 進行期（ステージIIB～IV）の菌状息肉症の治療 treatment of advanced stage iib to iv mycosis fungoides
4. 慢性移植片対宿主病の治療 treatment of chronic graft versus host disease
5. Vitiligo: Management and prognosis

English Journal

Phototherapy for pityriasis lichenoides: our experience.

Macias VC, Marques-Pinto G, Cardoso J.SourceHospital de Curry Cabral, Dermatology and Venereology Department, Lisbon, Portugal. vmcmacias@gmail.com
Cutaneous and ocular toxicology.Cutan Ocul Toxicol.2013 Jun;32(2):124-7. doi: 10.3109/15569527.2012.717572. Epub 2012 Sep 13.
Pityriasis lichenoides is a benign disease that includes a continuous spectrum with two polar ends: pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC). Although its benign and self-limited character, treatment is required, both for itch relief and for cos
PMID 22974328

Comparison of clinical and cost-effectiveness of psoralen + ultraviolet A versus psoralen + sunlight in the treatment of chronic plaque psoriasis in a developing economy.

Aggarwal K, Khandpur S, Khanna N, Sharma VK, Pandav CS.SourceDepartments of Dermatology & Venereology Community Medicine, All India Institute of Medical Sciences, New Delhi, India.
International journal of dermatology.Int J Dermatol.2013 Apr;52(4):478-85. doi: 10.1111/j.1365-4632.2012.05692.x. Epub 2013 Feb 22.
Psoralen + ultraviolet A (PUVA) therapy is an established modality for psoriasis. As India is a tropical country that has good availability of natural sunlight psoralen + sunlight (PUVAsol) may be a more convenient option. To compare the efficacy and cost-effectiveness of PUVA versus PUVAsol
PMID 23431966