PUVA

What is PUVA?

PUVA stands for psoralen combined with ultraviolet A (UVA) treatment. Psoralens are found in plants and can be sensitised when taken either orally or when applied topically.

Interestingly, they were used for this purpose in ancient Egypt but have only been commercially manufactured in the last four to five decades. When used with UVA (long-wave radiation) they allow for a lower dose of UVA.

PUVASOL is the use of psoralens with natural sunlight in areas such as India - research so far suggests it may be as good as conventional therapy. However, for many countries, sunlight is unpredictable and it is difficult to get the correct dose.¹

Indications¹

• Eczéma.

• Psoriasis.

• Vitiligo.

• Mycosis fungoides.

• Photodermatoses.

• Localised scleroderma.

• Skin changes associated with systemic lupus erythematosus (SLE).

Method of action

It remains unknown as to why psoralens with UVA work in the above conditions but it has been postulated to relate to modulation of the skins immune system.²

How is PUVA administered?¹

For oral PUVA, psoralen is taken 1-2 hours before treatment. For bathwater PUVA, the patient soaks in a bath containing a solution of psoralens. During treatment, the patient usually stands in a cabinet containing 24 or more 6-foot long UVA fluorescent bulbs. In most cases, treatment is undertaken 2-3 times each week for about 12 weeks.

The patient should always wear goggles to protect the eyes from exposure to the radiation. Clothes only need to be removed from the area to be treated, but groin protection is required. Those patients requiring treatment to small areas only may be treated using a smaller hand and foot unit (localised PUVA).

Exposure to sunlight should be avoided for 24 hours after the session.

Summary of special precautions required before PUVA treatment (see above)

• Eye protection - wear goggles.

• Groin protection - wear protective shield/garment.

• Skin and eye protection for 24 hours following the session of PUVA.

Effets indésirables¹

• Burning: an overdose of PUVA results in a sunburn-like reaction called phototoxic erythema. It is more likely in fair-skinned patients who sunburn easily. A burn is most likely 48–72 hours after the first 2 or 3 treatments. Sensitive areas such as breasts and buttocks may need to be covered for all or part of the treatment. Avoid photosensitisers such as certain oral medications, perfumes, cosmetics and applications of coal tar. Phototoxic erythema can persist for longer than sunburn from natural sunlight. Moisturisers and painkillers can reduce discomfort.

• Démangeaisons: temporary mild pricking or itching of the skin is common after treatment. The skin is often dry, so applying a moisturiser frequently and antihistamine tablets may help.

• Nausée occurs in a quarter of those treated with psoralens. Antiemetic tablets can be prescribed.

• Tanning: PUVA usually leads to tanning which lasts several months. Although the skin appears brown it may still burn easily on sun exposure. Tanning from UVA is not as protective as tanning from combined wavelengths occurring in natural sunlight.

• Dommages oculaires: if the eyes are not protected, keratitis may occur, causing red sore gritty eyes. Dark wrap-around glasses should be worn for the rest of the day after taking oral psoralens. Damage to the lens in the eye leading to cataracts is another possible risk.

• Skin ageing and skin cancer: fair-skinned and those with previous sun or radiation damage are most at risk. This is not a concern for most patients, who receive PUVA therapy for two or three months only.

  • Extensive PUVA treatment results in premature ageing changes and can increase the chance of skin cancer, particularly squamous cell carcinoma, and less often, basal cell carcinoma and melanoma.

  • Dry skin and wrinkles.

  • Discolouration, with broken blood vessels, freckles, lentigines.

Use in specific conditions

Psoriasis

• Used in older patients and those with severe psoriasis.

• Chronic plaque-type psoriasis is associated with up to 100% clearance.

• Efficacy is enhanced when combined with ultraviolet B (UVB) or medications such as methotrexate (especially pustular and erythrodermic forms).

• PUVA therapy has been compared with narrow-band UVB therapy in a randomised controlled trial which reported that the former is more effective.³

• Home phototherapy is likely to become an option for selected patients.^{4 5}

Voir aussi l'article sur Psoriasis en plaques chronique.

Eczema or dermatitis

• Moderate-to-severe eczema only. See also the article on Atopic Dermatitis and Eczema.

Mycose fongoïde

• This is a rare form of cutaneous T-cell lymphoma. See also the article on Mycose Fongoïde.

• PUVA can clear the disease but recurrence occurs in half of patients - with 30-50% remaining free of neoplasia at ten years.⁶

• It requires ongoing treatment over many years and thus may be associated with skin damage and neoplasia.⁶

Vitiligo

PUVA can lead to repigmentation in areas where there is complete loss of pigmentation - but results are variable. A Cochrane review found inadequate evidence for any particular treatment for vitiligo, including PUVA, and recommended that further studies are needed.⁷ Voir aussi l'article sur Vitiligo.