Category Archives: Therapies

Iontophoresis

Definition:
Iontophoresis is a process of transdermal drug delivery by use of a voltage gradient on the skin. Molecules are transported across the stratum corneum by electrophoresis and electroosmosis and the electric field can also increase the permeability of the skin. These phenomena, directly and indirectly, constitute active transport of matter due to an applied electric current. The transport is measured in units of chemical flux, commonly µmol/(cm2*hour). Iontophoresis has experimental, therapeutic and diagnostic applications.

Uses:
Laboratory uses:
Iontophoresis is useful in laboratory experiments, especially in neuropharmacology.[5] Transmitter molecules naturally pass signals between neurons. By microelectrophoretic techniques, including microiontophoresis, neurotransmitters and other chemical agents can be artificially administered very near living and naturally functioning neurons, the activity of which can be simultaneously recorded. This is used to elucidate their pharmacological properties and natural roles.

Therapeutic uses:
Therapeutically, electromotive drug administration (EMDA) delivers a medicine or other chemical through the skin. In a manner of speaking, it is an injection without a needle, and may be described as non-invasive. It is different from dermal patches, which do not rely on an electric field. It drives a charged substance, usually a medication or bioactive agent, transdermally by repulsive electromotive force, through the skin. A small electric current is applied to an iontophoretic chamber placed on the skin, containing a charged active agent and its solvent vehicle. Another chamber or a skin electrode carries the return current. One or two chambers are filled with a solution containing an active ingredient and its solvent vehicle. The positively charged chamber, called the anode, will repel a positively charged chemical species, whereas the negatively charged chamber, called the cathode, will repel a negatively charged species into the skin.

It is used to treat some types of palmar-plantar hyperhidrosis. In the treatment of hyperhidrosis, tap water is often the chosen solution for mild and medium forms. In very serious cases of hyperhidrosis, a solution containing glycopyrronium bromide or glycopyrrolate, a cholinergic inhibitor, can be used.

Diagnostic uses:
Iontophoresis of acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium-dependent generation of nitric oxide and subsequent microvascular vasodilation. Acetylcholine is positively charged and is therefore placed in the anode chamber.

Pilocarpine iontophoresis is often used to stimulate sweat secretion, as part of cystic fibrosis diagnosis.

Reverse iontophoresis is a technique by which molecules are removed from within the body for detection. The negative charge of the skin at buffered pH causes it to be permselective to cations such as sodium and potassium ions, allowing iontophoresis which causes electroosmosis, solvent flow towards the anode. Electroosmosis then causes electrophoresis, by which neutral molecules, including glucose, are transported across the skin. This is currently being used in such devices as the GlucoWatch, which allows for blood glucose detection across skin layers.

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Therapetic use in excessive sewating:

During this treatment, you sit with your hands, feet, or both in a shallow tray of water for about 20 to 30 minutes, while a low electrical current travels through the water. No one knows exactly how this treatment works, but experts believe it blocks sweat from getting to your skin’s surface. You’ll have to repeat this treatment at least a few times a week, but after several times you may stop sweating. Once you learn how to do iontophoresis, you can buy a machine to use at home. Some people only require a couple of treatments a month for maintenance.

CLICK TO SEE : Iontophoresis in Pain Management

Caution: Reliability of sources needs checking by experts in these fields.

Resources:
https://en.wikipedia.org/wiki/Iontophoresis

Cryosurgery

Definition:
Cryosurgery is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. The term comes from the Greek words cryo.

It is a proceedure of destruction of tissue by application of extreme cold; silver nitrate and solid carbon dioxide are commonly used. Uses include treatment of certain malignant lesions of the skin and mucous membranes, early removal of malignant lesions of the uterine cervix, and treatment of tumors that cannot be handled with traditional surgical techniques.

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Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions.
Cryotherapy procedures are usually performed in the doctor’s office.

Uses:
Warts, moles, skin tags, solar keratoses, Morton’s neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer, prostate cancer, lung cancer, oral cancers, cervical disorders and, more commonly in the past, hemorrhoids. Soft tissue conditions such as plantar fasciitis[4] (jogger’s heel) and fibroma (benign excrescence of connective tissue) can be treated with cryosurgery. Generally, all tumors that can be reached by the cryoprobes used during an operation are treatable. Although found to be effective, this method of treatment is only appropriate for use against localized disease, and solid tumors larger than 1 cm. Tiny, diffuse metastases that often coincide with cancers are usually not affected by cryotherapy.

Cryosurgery works by taking advantage of the destructive force of freezing temperatures on cells. When their temperature sinks beyond a certain level ice crystals begin forming inside the cells and, because of their lower density, eventually tear apart those cells. Further harm to malignant growth will result once the blood vessels supplying the affected tissue begin to freeze.

Specific examples include nerve irritation between the ribs (intercostal neuralgia), cluneal nerve entrapment, ilioinguinal neuroma, hypogastric neuromas, lateral femoral cutaneous nerve entrapment, and interdigital neuromas. Many forms of nerve entrapment can often be treated with cryotherapy.

Method of doing:

Liquid nitrogen
A common method of freezing lesions is using liquid nitrogen as the cooling solution. This ?196 °C (?321 °F) cold liquid may be sprayed on the diseased tissue, circulated through a tube called a cryoprobe, or simply dabbed on with a cotton or foam swab.

Carbon dioxide
Carbon dioxide is also available as a spray and is used to treat a variety of benign spots. Less frequently, doctors use carbon dioxide “snow” formed into a cylinder or mixed with acetone to form a slush that is applied directly to the treated tissue.

Argon
Recent advances in technology have allowed for the use of argon gas to drive ice formation using a principle known as the Joule-Thomson effect. This gives physicians excellent control of the ice, and minimizing complications using ultra-thin 17 gauge cryoneedles.

Freeze sprays
A mixture of dimethyl ether and propane is used in some “freeze spray” preparations such as Dr. Scholl’s Freeze Away. The mixture is stored in an aerosol spray type container at room temperature and drops to ?41 °C (?42 °F) when dispensed. The mixture is often dispensed into a straw with a cotton-tipped swab. Similar products may use tetrafluoroethane or other substances.

Pruducts:
Cryosurgical systems
A number of medical supply companies have developed cryogen delivery systems for cryosurgery. Most are based on the use of liquid nitrogen, although some employ the use of proprietary mixtures of gases that combine to form the cryogen.

In cancer treatment
Cryosurgery is also used to treat internal and external tumors as well as tumors in the bone. To cure internal tumors, a hollow instrument called a cryoprobe is used, which is placed in contact with the tumor. Liquid nitrogen or argon gas is passed through the cryoprobe. Ultrasound or MRI is used to guide the cryoprobe and monitor the freezing of the cells. This helps in limiting damage to adjacent healthy tissues. A ball of ice crystals forms around the probe which results in freezing of nearby cells. When it is required to deliver gas to various parts of the tumor, more than one probe is used. After cryosurgery, the frozen tissue is either naturally absorbed by the body in the case of internal tumors, or it dissolves and forms a scab for external tumors.

Proceedures:
Your preparation for cryosurgery depends on the type of cryosurgery being performed. Cryosurgery for skin cancer, which is the main reason cryosurgery is used, requires little preparation on your part.

If your doctor is treating an internal organ with cryosurgery, you’ll probably be given the same instructions that you’d get before traditional surgery. You’ll be asked to fast for 12 hours beforehand and arrange for a ride home from the procedure.

Before the procedure, tell your doctor if you have an allergy to anesthesia, as well as any and all medicine you’re taking, including over-the-counter medications and nutritional supplements.

Your doctor will provide you with complete instructions for preparing for the surgery. It’s important that you follow them.

Your doctor will place liquid nitrogen on your skin using a cotton swab or spray. A numbing medicine may be used to prevent any pain or discomfort.

If an internal area is being treated, your surgeon will use a scope, which is a flexible tube that can fit into various openings in your body, such as the urethra, rectum, or a surgical incision. The liquid nitrogen is fed to the area under treatment and applied to the targeted cells. The cells freeze, die, and then will be slowly absorbed by your body.

Your doctor will use imaging equipment, such as an ultrasound, as a guide for carrying out the procedure.

Results
Cryosurgery is a minimally invasive procedure, and is often preferred to more traditional kinds of surgery because of its minimal pain, scarring, and cost; however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to nerve tissue is of particular concern.

Patients undergoing cryosurgery usually experience redness and minor-to-moderate localized pain, which most of the time can be alleviated sufficiently by oral administration of mild analgesics such as ibuprofen, codeine or acetaminophen (paracetamol). Blisters may form as a result of cryosurgery, but these usually scab over and peel away within a few days.

Side effects:
While cryotherapy can reduce unwanted nerve irritation, it sometimes can leave the tissue affected with unusual sensations, such as numbness or tingling, or with redness and irritation of the skin. But these effects are generally temporary.

Risk factors:
Cryosurgery does have risks, but they’re considered lower than other cancer treatments, such as surgery and radiation.

The risks associated with cryosurgery include:

*blisters
*damage to nearby healthy tissue or vessels
*infection
*a loss of sensation if nerves are affected
*pain
*scarring
*sexual dysfunction
*ulcers
*white skin at the site of the surgery

Resources:
https://en.wikipedia.org/wiki/Cryosurgery
https://medical-dictionary.thefreedictionary.com/cryosurgery
https://www.healthline.com/health/cryosurgery#purpose

Mastectomy

Description:
A mastectomy is surgery to remove all breast tissue from a breast as a way to treat or prevent breast cancer.

For those with early-stage breast cancer, a mastectomy may be one treatment option. Breast-conserving surgery (lumpectomy), in which only the tumor is removed from the breast, may be another option.

Deciding between a mastectomy and lumpectomy can be difficult. Both procedures are equally effective for preventing a recurrence of breast cancer. But a lumpectomy isn’t an option for everyone with breast cancer, and others prefer to undergo a mastectomy.

Both mastectomy and lumpectomy are referred to as “local therapies” for breast cancer, targeting the area of the tumor, as opposed to systemic therapies, such as chemotherapy, hormonal therapy, or immunotherapy.

Traditionally, in the case of breast cancer, the whole breast was removed. Currently, the decision to do the mastectomy is based on various factors, including breast size, the number of lesions, biologic aggressiveness of a breast cancer, the availability of adjuvant radiation, and the willingness of the patient to accept higher rates of tumor recurrences after lumpectomy and radiation. Outcome studies comparing mastectomy to lumpectomy with radiation have suggested that routine radical mastectomy surgeries will not always prevent later distant secondary tumors arising from micro-metastases prior to discovery, diagnosis, and operation.

Newer mastectomy techniques can preserve breast skin and allow for a more natural breast appearance following the procedure. This is also known as skin-sparing mastectomy.

Surgery to restore shape to your breast — called breast reconstruction — may be done at the same time as your mastectomy or during a second operation at a later date.

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Types:
Currently, there are several surgical approaches to mastectomy, and the type that a person decides to undergo (or whether she or he will decide instead to have a lumpectomy) depends on factors such as the size, location, and behavior of the tumor (if one is present), whether or not the surgery is prophylactic, and whether the person intends to undergo reconstructive surgery.

* Simple mastectomy (or “total mastectomy”): In this procedure, the entire breast tissue is removed, but axillary contents are undisturbed. Sometimes the “sentinel lymph node”—that is, the first axillary lymph node that the metastasizing cancer cells would be expected to drain into—is removed.

* Modified radical mastectomy: The entire breast tissue is removed along with the axillary contents (fatty tissue and lymph nodes). In contrast to a radical mastectomy, the pectoral muscles are spared. This type of mastectomy is used to examine the lymph nodes because this helps to identify whether the cancer cells have spread beyond the breasts.

* Radical mastectomy (or “Halsted mastectomy”): First performed in 1882, this procedure involves removing the entire breast, the axillary lymph nodes, and the pectoralis major and minor muscles behind the breast.

* Skin-sparing mastectomy: In this surgery, the breast tissue is removed through a conservative incision made around the areola (the dark part surrounding the nipple).

* Nipple-sparing/subcutaneous mastectomy: Breast tissue is removed, but the nipple-areola complex is preserved. This procedure was historically done only prophylactically or with mastectomy for the benign disease over the fear of increased cancer development in retained areolar ductal tissue. Recent series suggest that it may be an oncologically sound procedure for tumors not in the subareolar position.

* Extended Radical Mastectomy: Radical mastectomy with intrapleural en bloc resection of internal mammary lymph node by sternal splitting.

* Prophylactic mastectomy: This procedure is used as a preventative measure against breast cancer. The surgery is aimed to remove all breast tissue that could potentially develop into breast cancer.

Risks Factors:

Risks of a mastectomy include:

* Bleeding
* Infection
* Pain
* Swelling (lymphedema) in your arm if you have an axillary node dissection
* Formation of hard scar tissue at the surgical site
* Shoulder pain and stiffness
* Numbness, particularly under your arm, from lymph node removal
Buildup of blood in the surgical site (hematoma)

Before surgery:
Before the operation, everyone will meet with the surgeon a few days before the surgery or even the day before, however, a much longer period is very beneficial since it allows the patient for a more objective weighing of the options. Although there is some urgency in timing the surgery, the patient needs some time after the initial shock of hearing the cancer verdict; otherwise, she may later regret her decision. The extent and specific details regarding the mastectomy will be discussed along with the person’s medical history.

Of extreme importance will be the woman’s decision whether the entire breast is to be removed, or only a part of it – and that is usually much more a personal choice than a medical assessment. The medical viewpoint stresses the statistical fact of much stronger chances for cure and survival when the breast is removed completely, even when the size of the cancer is small. From the personal viewpoint, the perspective of not having the breast is very painful and difficult to accept. At this point the support of the family and of good friends can make the difference between life and death, since it is easier for friends to present the after-the-surgery future in the “matter of fact” way, thus facilitating the reasonable decision. The dilemma of the vital importance will be weighing the aesthetics and pride, against the chances of curing and surviving, which are much better when the breast is removed 100% completely. During these considerations, very painful indeed, one needs to realize that a woman’s flat chest without breasts, even without nipples, does not look bad at all, nothing to feel embarrassed of, or to be ashamed by; it looks just neutral – much better than a partly removed, disfigured breast. Since the surgery is unavoidable, for people open to see the problem in this way, the choice becomes easier.

Before the surgery the person will have time to ask any questions regarding the procedure at this time and after everything is addressed a consent form is signed. Information about not eating or drinking anything beforehand will be gone over as well. The person will also meet with the anesthesiologist or the health professional who is going to be giving the anesthesia the day of the operation.[2][citation needed]

Recent research has indicated that mammograms should not be done with any increased frequency than normal procedure in people undergoing breast surgery, including breast augmentation, mastopexy, and breast reduction.[12]

During surgery:
The day of the operation the person will have an IV line started, which will be used to give medicine. Since this is an extensive procedure the person will be hooked up to an EKG machine and also have a blood pressure cuff to monitor vitals and the heart rhythm throughout the whole surgery. The anesthesia will be given, which will result in the person going to sleep. The timing of the surgery all depends on the extent and what type of mastectomy the person will be having.

After surgery:
When the procedure is complete the patient will be taken to a recovery room where they are monitored until they wake up and their vital signs remain stable. It is normal for people that have mastectomies to remain in the hospitals for 1 to 2 nights and they are released to go home if they are doing well. The decision for discharge should be made by the doctor based on the person’s overall health at the time. The person is dressed with a bandage over the surgery site that is wrapped around the chest snugly. It is common to have drains coming from the incision site to help remove blood and lymph to initiate the healing process. Patients may have to be taught to empty, care, and measure the fluid from the drains. Measuring the fluids will help identify any problems the doctors need to be aware of. Patients should be taught the effects of the surgery, such as regular activity may be altered. There is a possibility that pain, numbness, or tingling in the chest and arm could continue long after the surgery has been done. It is recommended that patients see their surgeon 7–14 days after the surgery, during this time the doctor will explain the results and talk about further treatment if needed such as radiation and chemotherapy. The doctor might refer the patient to a plastic surgeon if she showed interest in breast reconstruction surgery.

Resources:
https://en.wikipedia.org/wiki/Mastectomy
https://www.mayoclinic.org/tests-procedures/mastectomy/about/pac-20394670

EECP Therapy

Enhanced external counterpulsation (EECP) is a mechanical form of treatment for angina. While several clinical studies appear to show that this treatment can be helpful in reducing symptoms of angina in patients with coronary artery disease (CAD), EECP has yet to be accepted by most cardiologists, and has not entered the mainstream of cardiology practice.

What is EECP?
EECP is a mechanical procedure in which long inflatable cuffs (like blood pressure cuffs) are wrapped around both of the patient’s legs. While the patient lies on a bed, the leg cuffs are inflated and deflated synchronously with each heartbeat. The inflation and deflation are controlled by a computer, which uses the patient’s ECG to trigger inflation early in diastole (when the heart relaxes and is filled with blood), and deflation just as systole (heart contraction) begins. The inflation of the cuffs occurs sequentially, from the lower part of the legs to the upper, so that the blood in the legs is “milked” upwards, toward the heart.

EECP has at least two potentially beneficial actions on the heart. First, the milking action of the leg cuffs increases the blood flow to the coronary arteries during diastole. (The coronary arteries, unlike other arteries in the body, receive their blood flow in between heartbeats, instead of during each heartbeat.) Second, by its deflating action just as the heart begins to beat, EECP creates something like a sudden vacuum in the arteries, which reduces the work the heart muscle has to perform in pumping blood. It is also speculated that EECP may help reduce endothelial dysfunction.

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EECP is administered as a series of outpatient treatments. Patients receive 5 one-hour sessions per week, for 7 weeks (for a total of 35 sessions). The 35 one-hour sessions are aimed at provoking long lasting beneficial changes in the circulatory system.

How Effective Is EECP?
Several studies suggest that EECP can be quite effective in treating chronic stable angina. A small randomized trial showed that EECP significantly improved both the symptoms of angina (a subjective measurement) and exercise tolerance (a more objective measurement) in patients with CAD. EECP also significantly improved “quality of life” measures, as compared to placebo therapy. Other studies have shown that the improvement in symptoms following a course of EECP seems to persist for up to five years (though 1 in 5 patients may require another course of EECP to maintain their improvement).

How Does EECP Work?
The mechanism for the apparent sustained benefits seen with EECP is unknown. There is some evidence suggesting that EECP can help induce the formation of collateral vessels in the coronary artery tree, by stimulating the release of nitric oxide and other growth factors in within the coronary arteries. There is also evidence that EECP may act as a form of “passive” exercise, leading to the same sorts of persistent beneficial changes in the autonomic nervous system that are seen with real exercise.

Can EECP Be Harmful?
EECP can be somewhat uncomfortable, but is generally not painful. In studies, the large majority of patients have tolerated the procedure quite well.

But not everyone can have EECP. People probably should not have EECP if they have aortic insufficiency, or if they have had a recent cardiac catheterization, an irregular heart rhythm such as atrial fibrillation, severe hypertension, peripheral artery disease involving the legs, or a history of deep venous thrombosis. For anyone else, however, the procedure appears to be safe.

When Is EECP Recommended?
Based on what we know today, EECP should be considered in anybody who still has angina despite maximal medical therapy, and in whom stents or bypass surgery are deemed not to be good options. Medicare has approved coverage for EECP for patients with angina who have exhausted all their other choices.

In 2014, several professional organizations (the American College of Cardiology, American Heart Association, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons) finally agreed in a focused update that EECP ought to be considered for patients with angina refractory to other treatments.

Why Isn’t EECP Used More Often?
In general, the cardiology community has largely chosen to ignore such an outlandish form of therapy, and many cardiologists fail to to even consider offering EECP as a therapeutic option. Consequently, most patients who have angina never hear about it.

Indeed, EECP is a little outlandish. It certainly does not look like cardiology. Nobody can really explain how it works. And, from a cardiologist/s viewpoint, when you compare the relative effort and relative reimbursement of EECP to something like inserting a stent (35 sessions over 7 weeks vs. a 30-minute procedure) there is no contest. To expect cardiologists to embrace EECP with any enthusiasm simply ignores human nature.

Still, when a noninvasive treatment for angina exists that is safe and well tolerated, when available evidence (as imperfect as it may be) strongly suggests the treatment is quite effective in many patients, and when the patient being treated will be able to tell pretty definitively whether or not the treatment has helped in their own individual case (by the presence or absence of a substantial reduction in angina symptoms), it does not seem unreasonable to allow patients with stable angina to opt for a trial of that noninvasive therapy, perhaps even before they are pushed into invasive therapy.

If you are being treated for stable angina and still have symptoms despite therapy, it is entirely reasonable for you to bring up the possibility of trying EECP. Your doctor should be quite willing to discuss this possibility with you, objectively and without prejudice.

Resources:
https://www.verywellhealth.com/enhanced-external-counterpulsation-eecp-1745293

PUVA therapy

Description:
PUVA is an acronym. The P stands for psoralen,(Psoralen is a photosensitizing agent found in plants ) the U for ultra, the V for violet, and the A for that portion of the solar spectrum between 320 and 400 nanometers in wavelength. Psoralens are chemicals found in certain plants that have the ability to absorb ultraviolet light in these wavelengths. Once the light energy is absorbed, these chemicals are energized to interact with DNA, ultimately inhibiting cell multiplication, which is their presumed mode of action.

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Certain skin diseases are characterized by cells that are rapidly multiplying. Inhibiting this unrestrained multiplication can be useful in treating these diseases. So PUVA is a combination of an oral drug and subsequent ultraviolet light exposure. The treatment may affect certain blood cells and skin cells so that the skin disease improves.

It is a 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. 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.

Plant sources   from where  we get psoralens:
Ficus carica (fig) is probably the most abundant source of psoralens. They are also found in small quantities in Ammi visnaga (bisnaga), Pastinaca sativa (parsnip), Petroselinum crispum (parsley), Levisticum officinale (lovage), Foeniculum vulgare (fruit, i.e., fennel seeds), Daucus carota (carrot), Psoralea corylifolia (babchi), and Apium graveolens (celery).

Types of PUVA therapy:
The most common form of therapy combines 8-methoxypsoralen taken by mouth followed 45-60 minutes later by exposure of the skin to UVA. Less commonly the drug is applied topically (the medication is occasionally diluted in bathtub water in which the patient is immersed) and then after a few minutes the ultraviolet exposure occurs.

Procedure:
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.

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.

How maney PUVA  therapy is required:
There ought to be a significant improvement in the patient’s skin disease after about 15 treatments. Treatments are given no sooner than 48 hours apart because the burn induced by PUVA is often delayed for as long as two days (unlike ordinary sunburns). Unless there is a problem, the amount of energy administered to the patient is increased appropriately at each visit depending on the patient’s coloration. After about 30 treatments, a decision is made as to whether to continue treatments. PUVA is not always effective. If there is no improvement after these treatments, it is probably unlikely that continuing this form of treatment is worthwhile. On the other hand, if significant clearing has occurred, it is probably prudent to decrease the frequency of treatments in order to maintain the improvement. Since there is a relationship between the amount of light energy administered and the degree of photo-aging and the induction of skin cancers, it is wise to limit the light exposures as appropriate.

Advantages:
The major advantage to PUVA is that it is an effective therapy that becomes active only at the site of the disease, the skin. It can be used to treat large areas of skin, and the fact that the drug is only activated in the presence of UV light implies that it may be less toxic than other therapies that require systemic administration and whose effects are not localized to just the skin.

PUVA must be administered in a physician’s office under the control of a medical professional so it requires repeated visits to the office. PUVA may not cure psoriasis permanently so treatment can be required indefinitely.

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.

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 since ancient Egypt but have only been available in a chemically synthesized form since the 1970s.

Resources:
http://en.wikipedia.org/wiki/PUVA_therapy
http://www.medicinenet.com/puva_therapy_photochemotherapy/article.htm