Photochemotherapy, also known as PUVA, is a form of ultraviolet radiation therapy (phototherapy) used to treat serious skin conditions.
What is PUVA?
PUVA is a combined treatment that includes Psoralens (P) and then UVA exposure to the skin (long wave ultraviolet radiation). Since 1976, it has been available in its current form.
Psoralens are plant-derived chemicals that render the skin UVA sensitive for a short period of time. Thousands of years ago, the ancient Egyptians were the first to employ psoralens to treat skin disorders. Methoxsalen (8-methoxypsoralen), 5-methoxypsoralen, and trisoralen are examples of medicine psoralens.
Methoxsalen capsules are given two hours before the treatment appointment for oral PUVA. The patient soaks in a bath with a psoralens solution for bathwater PUVA. Treatment is usually done twice or three times a week in most cases.
Typically, the patient stands in a cabinet with 24 or more 6-foot long UVA fluorescent lamps during therapy.
To protect their eyes from radiation, the patient should constantly wear goggles.
For full-body exposure, he or she is usually simply dressed in underpants. If only the arms and legs are exposed to the radiation, the patient should wear the same clothing for each session to avoid accidentally exposing a new patch of skin.
The UVA lamps are turned on for longer and longer periods of time, starting at around one minute and going up to half an hour. The cabinet may be cooled with ventilation or air conditioning, as it tends to get very hot with longer treatment sessions.
Patients who just require treatment to a few minor locations may be treated with a tiny hand and foot unit. It’s possible that PUVA from bathwater will suffice. In this situation, the hands and/or feet are bathed for 30 minutes in a weak solution of methoxsalen before being exposed to UVA.
A few people may benefit from topical PUVA, which involves applying a psoralens lotion or gel to the afflicted areas 10 minutes before UVA exposure.
Can sunlight be used for PUVA?
In the absence of PUVA cabinets, some physicians advise patients to be exposed to sunshine after ingesting psoralens or applying psoralens topically. Trisoralen has traditionally been used as an oral psoralen since it is slightly safer than methoxsalen.
Unfortunately, sunshine is unreliable, making it difficult to receive the right amount. It’s ineffectual if there’s too little of it. If you use too much, you could get a horrible blistering burn.
What are the side effects and risks of PUVA?
Phototoxic erythema is a sunburn-like reaction caused by an excessive amount of PUVA. It is more common in fair-skinned patients who are prone to sunburn. After the first two or three treatments, a burn is most likely 48–72 hours later. Breasts and buttocks, for example, may need to be covered for all or part of the therapy. Avoid photosensitizers such some oral drugs, fragrances, cosmetics, and coal tar treatments. The UVA dose should not be raised if the treated skin turns pink. It’s possible that one or more treatments will go unnoticed. Phototoxic erythema, on the other hand, can last far longer than sunburn from natural sunshine. Moisturizers and pain relievers can help to alleviate discomfort.
Following treatment, moderate prickling or itching of the skin is usual. The skin is usually dry. Use a moisturizer on a regular basis. Tablets containing antihistamines might occasionally assist.
Nausea affects a quarter of persons who use psoralens. Tell your phototherapy nurse or doctor if this happens. If the methoxsalen capsules are taken with food or the dose is reduced, nausea is lessened. Antiemetic pills are available on prescription.
PUVA causes tanning that lasts for several months. Even if the skin seems brown, it can still burn quickly when exposed to the sun. UVA tanning is not as protective as tanning with a combination of wavelengths seen in natural sunlight.
Keratitis can develop if the eyes are not protected from UV exposure. This causes red, stinging, gritty eyes, which can be quite unpleasant. After taking oral psoralens, wear dark wrap-around glasses for the remainder of the day.
Another concern is damage to the eye’s lens, which can lead to cataracts.
Skin ageing and skin cancer
Extensive PUVA treatment results in premature ageing changes and can increase the chance of skin cancer.
- Dry skin and wrinkles
- Discolouration: broken blood vessels, freckles, lentigines
- Squamous cell carcinoma, and less often, basal cell carcinoma and melanoma
Individuals with fair skin or who have had previous sun or radiation damage are the most vulnerable. Most patients who take PUVA therapy for two or three months are unconcerned about this.
Patients on long-term maintenance medication should see a dermatologist at least once every six months. Any new moles, slow-healing wounds, or developing lumps should be brought to the doctor’s notice.
Skin malignancies are usually, but not always, treatable. It’s not a good idea to keep using PUVA if severe ageing changes or skin malignancies appear.
There is no proof that PUVA causes harm to a developing fetus. However, if a woman becomes pregnant or suspects she is pregnant while on PUVA treatment, we encourage her to cease the treatment immediately.
Instructions for PUVA patients
Follow the advice of the phototherapy nurse and your dermatologist if you are undergoing PUVA therapy. Some general recommendations are:
- Keep all scheduled appointments. Allow time for changing.
- Tell the staff about your health problems, including medications and eye disease.
- Do not apply any ointments or cosmetics (especially perfumes and coal tar products) except as directed by your doctor or phototherapist.
- Schedule treatments at the same time of day whenever possible.
- Always take the capsules at exactly the same interval before the UVA exposure.
- Ideally, take the capsules two hours after a meal.
- Alcohol consumption should be minimal.
- Avoid sun exposure on treatment and non-treatment days.
- Apply broad-spectrum sunblock to face and hands before treatment.
- Cover male genitalia – this area must not be exposed to UVA.
- You must protect your skin and eyes from natural sunlight for twelve hours after taking methoxsalen tablets.
- During treatment, you must wear special goggles provided.
- Wear wrap-around ultraviolet-protective sunglasses both indoors and outdoors, from the moment you take the methoxsalen tablets until nightfall on the treatment day.
- After dark, the glasses must still be worn under fluorescent lighting, but are not necessary outside or with incandescent lamps.
- Wear fully covering clothing outdoors and if near a window indoors, i.e. hats, long sleeves and skirts or trousers.
- Apply sunscreen to all uncovered skin after a treatment.
- In some circumstances polarised or prescription glasses may be suitable; they must cut out all UV radiation. You can use clear perspex glasses indoors.
- Arrange to be seen regularly by your dermatologist.
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