PUVA

course

Since being clinically validated by the Federal Food and Drug Administration (FDA) in 1982, PUVA has become an important treatment for refractory psoriasis. About one-third of US dermatologists offer PUVA treatment. For many patients, PUVA has become the preferred treatment for their control of psoriasis. PUVA provides hospitalization opportunities for those with severe psoriasis.

A 25-year study sponsored by the government has accumulated a large amount of material on long-term use of PUVA, which provides long-term risk and benefit data not available in other psoriasis therapies.

PUVA - Psoralen plus UVA

Psoralen itself does not treat psoriasis. It is a plant extract that is administered orally or externally to the skin. Psoralen interacts with UVA rays that illuminate the skin to delay psoriatic skin. The loss is generated. It can be used to treat systemic psoriasis, as well as for psoriasis in isolated areas such as the hands and feet. PUVA can also be used in combination with other therapies.

Studies have shown that PUVA enables at least 80% of psoriasis to be substantially or completely eliminated, and long-term relief can be achieved even without maintenance. PUVA can reduce skin lesions for several months to more than one year.

PUVA therapy

PUVA treatment should be performed at the doctor's office. When psoralen is taken orally or applied to the skin, the patient exposes the patient's lesion to UVA. UVA is produced by a light box that is filled with UV light. Most UVA devices are vertical, so the patient needs to stand upright during treatment. Other special UVA devices are only used to illuminate specific parts of the body such as the hands and feet.

The doctor and his colleagues should accurately grasp the interval between oral or topical psoralen and UVA irradiation. This is critical to the success of treatment. In order for UVA irradiation to work, UVA irradiation must be performed when psoralen reaches a high level in the skin.

Oral administration is the most common mode of administration for PUVA. Depending on the type of pill used, the patient needs to take the psoralen pill 75 to 120 minutes before entering the light box. The lesion site is then exposed to UVA.

The external use of PUVA refers to "smear", "wet" and "bath". "Smear" is to first make psoralen in ointment or liquid form, directly applied to the lesions of psoriasis, especially the palm and sole. "Infiltration" is to immerse the psoriatic lesions in water containing psoralen. Similarly, "bathing" is to soak the entire body in a tub filled with psoralen water. After psoralen is applied to the skin, UVA irradiation should be performed within 15 minutes. The effect of psoralen will be significantly reduced after one hour.

A-band UV in PUVA treatment

The initial UVA exposure time can be very short (30 seconds to several minutes), depending on the type of skin of the patient and the type of UVA light box device. The exposure time is gradually extended to 20 minutes or longer depending on the strength of the light box device. It takes about 25 treatments to clear the skin lesions. In some cases, especially when the condition is very severe, more treatments are needed.

PUVA treatment is usually performed two to three times a week, but the treatment may vary. PUVA produces a transient erythema (redness or tenderness in the skin) and the skin turns yellowish brown. Unlike sunburn, erythema caused by PUVA generally does not exceed 24 hours and usually peaks approximately 48 hours after treatment. Because erythema does not become apparent only after a period of treatment, PUVA treatment is usually not performed on a daily basis.

After the lesion is cleared, the patient's need for maintenance treatment depends on the severity of psoriasis. It may be necessary to maintain treatment only once or twice a month, but the specific treatment varies from person to person.

Which patients should consider PUVA treatment

PUVA is generally used in patients with moderate to severe psoriasis who are resistant to other therapies, or those who have physical or mental disabilities due to psoriasis, and can also be used in the initial treatment of elderly patients.

Stable plaque psoriasis, drip psoriasis, and psoriasis in the palm and sole are particularly suitable for PUVA treatment. Special UVA devices can be used to treat skin lesions in the palms and soles of the feet and other body-constrained areas.

PUVA treatment can also be used in patients who are sensitive or allergic to sunlight. Children or adolescents are generally not recommended for PUVA. However, if conventional treatments have unexpected side effects or are ineffective, PUVA treatment can also be used in younger patients.

Relative contraindications for PUVA treatment

Some patients are not suitable for PUVA treatment because of their past medical history, and the benefits of their treatment may not be as good as the harm. The following are relative contraindications for PUVA treatment (but not absolute):

Family history of allergies to sunlight

Pregnancy or lactation

History of arsenic intake (eg Fowler's solution)

Has received ionizing radiation therapy (Grenz line or X-ray)

Some diseases such as lupus erythematosus, porphyria or skin cancer need to be protected from light

The heart or blood pressure problem is so severe that it can't be heat-resistant or standing for a long time.

Skin cancer history

Liver disease (may cause an increase in the concentration of drugs in the blood, but patients with liver disease can use PUVA bath therapy)

Stomach problem

Side effects of PUVA

PUVA has some side effects. The most common short-term side effects of oral PUVA are nausea, itchy skin and redness.

Drinking milk or eating while taking psoralen can prevent nausea. Hard capsules can be taken with food or milk; soft capsules can be taken with low-fat foods or low-fat milk. The dose of psoralen can be divided into two. When taking, you can eat food at the same time. Each pill can be separated by several minutes.

PUVA can produce itching in two ways. First, PUVA dries the skin and makes the skin itchy; it can be relieved by moistening treatment. Second, some patients have severe recurrent itching after PUVA treatment because the peripheral nerves in the skin are temporarily damaged. Using antihistamines, scrubbing with oily wheat synthetics, or using a topical drug containing capsaicin, may help relieve itching.

Skin tenderness or blistering may occur immediately following PUVA treatment, but these symptoms can be alleviated by using a doctor-recommended medication. Swelling of the lower extremities caused by standing for a long time during treatment can be reduced by wearing protective socks.

Other rare side effects that may be associated with psoralen include depression, psoriasis, dizziness, insomnia, headache, nervousness, edema, herpes simplex recurrence, rash, and lower extremity spasms.

External PUVA can avoid some side effects of oral PUVA, and it can reduce the incidence of cataract. It is believed that topical PUVA can reduce the absorption of psoralen into the lens of the eye (a large number of follow-up studies of patients treated with PUVA, did not show the incidence of cataract Rise).

External PUVA produces a higher risk of skin burns when phototherapy is performed, and the intensity is more concentrated. However, it provides an opportunity for patients who cannot tolerate the side effects of oral psoralen. For example, patients with severe nausea and liver disease are treated with topical PUVA.

Topical PUVA can also be used in patients with refractory psoriasis rash because it enables a higher concentration of topical psoralen, so that only a lower dose of UVA is required to produce an effective therapeutic response. Moreover, those who are resistant to oral PUVA treatment may respond to topical PUVA treatment.

a precaution for your comfort

1. Protect sensitive areas: Advice on positive phototherapy - "Pill the pills and put on the glasses." You need to wear glasses or eye masks for 12 to 24 hours after taking the light-sensitive drugs and starting the PUVA treatment, including any sun. Where the light shines - even through the window, you don't need them until the sun sets. The TV does not emit ultraviolet light.

2. Glasses that block UVA are not necessarily black. The special coating allows transparent glasses to block UV light. However, the glasses used must have side panels to prevent leakage of light.

3. Male patients should protect their genitals during treatment unless the area is particularly in need of treatment because the male genital area is very susceptible to skin cancer. It can be protected with sports pads, shorts, towels or sunscreens. Women should use sunscreens on the nipple and the pigmentation areas around them.

4, sunscreen can protect unaffected skin. If there is no psoriasis in the neck, face, lips, ears or back of the hand, it should be protected during and after treatment. Since psoralen makes the skin very sensitive to the sun, you need to avoid accidental sun exposure after PUVA treatment. For example, if you are driving in the sun after treatment, you should wear gloves or use sunscreen to prevent burns. The glass of the window blocks UVB, but the UVA penetrates.

5. Report any new medications. Patients receiving PUVA must tell the doctor about new medications that begin at any time. Certain prescription and over-the-counter medications may increase the risk of burns, including some antibiotics, anticancer drugs, antidepressants, antihistamines, antihypertensives, antiparasitic drugs, antipsychotics, diuretics, hypoglycemic agents, Non-steroidal anti-inflammatory drugs, sunscreens and oral contraceptives. The dose of UVA with these drugs may require appropriate adjustments.

Avoid sunbathing: Sunbathing can induce erythema (skin burns), which is more likely to occur after PUVA treatment.

Protect your stomach: The nausea caused by PUVA can be alleviated by making a "pad" of food for psoralen in your stomach. It's like making a sandwich. First eat some cereals (a piece of fried dough, bread, biscuits or oatmeal), then take the medicine, then eat more cereals to make the top layer of the sandwich.

It is recommended that you try to keep the amount and type of food you eat consistently, while keeping the interval between eating and taking the medicine unchanged. This helps to align the psoralen levels for each treatment.

Ginger-containing capsules (available in health food stores) prove to be effective for some people. Patients who take ginger capsules 30 to 60 minutes before taking psoralen can alleviate nausea. Drinking ginger-containing light beer (or soda water with carbon dioxide) and eating ginger-containing desserts can also help.