Last updated date: 03-Mar-2023

Originally Written in English




Phototherapy is an excellent therapeutic option for a variety of disorders. Phototherapy has been used to treat chronic skin disorders such as psoriasis, vitiligo, and severe eczema for almost a century.

While many therapies suppress the general immune system, UV light can be utilized to suppress the skin's local immune system. Light treatment can also help to delay the growth of thick, scaly skin in disorders like psoriasis. UV light treatment is employed in vitiligo because of its capacity to activate melanocytes, the pigment-producing cells of the skin. This makes phototherapy a good treatment choice for almost anybody, especially those who dislike creams, prefer a natural, steroid-free treatment, or want more control utilizing a mix of therapies. Phototherapy is also an option to explore for youngsters and pregnant women.


What is Phototherapy?

Phototherapy Definition

Phototherapy, often known as light therapy, is the treatment of various wavelengths of ultraviolet (UV) radiation. It entails the controlled application of non-ionizing radiation to the skin in the treatment of different dermatoses.


Types of Phototherapy

Types of Phototherapy

  • Ultraviolet light B (UVB): UVB is found in natural sunshine and is an excellent psoriasis therapy. UVB enters the skin and decreases the proliferation of skin cells that are impacted. UVB phototherapy, excimer laser, and in-office or home UVB phototherapy are all options for treatment.
  • UVB phototherapy includes regularly exposing the skin to an artificial UVB light source for a specified amount of time. This treatment is given at a doctor's office or clinic, or at home using a phototherapy machine.

There are two types of UVB treatment: broad band and narrow band. There are three main differences between them:

  1. Narrow-band UVB light bulbs release a smaller range of ultraviolet light.
  2. Narrow-band UVB may clear psoriasis faster and produce longer remissions.
  3. Narrow-band UVB may require fewer treatments per week.

UVB therapy is available in a variety of forms. Small units for localized locations such as the hands and feet, full-body units, or hand-held devices are examples of this. Some UVB systems employ standard UV lamps or bulbs, while others employ LED bulbs.

The excimer laser, which has been authorized by the FDA for treating persistent, localized psoriasis plaques, delivers a high-intensity UVB beam.

The excimer laser can be used to treat mild-to-moderate psoriasis on the skin. According to research, it is a very effective therapy for scalp psoriasis. However, there is not currently enough long-term evidence to determine how long the benefits of laser therapy will remain.

Home UVB phototherapy for psoriasis might be a cost-effective and handy option. It, like phototherapy in a doctor's office or clinic, necessitates a constant treatment regimen. Individuals are initially treated at a medical institution before beginning to use a light unit at home. It is vital to follow a health care provider's instruction and continue with frequent check-ups while practicing phototherapy at home.

All phototherapy treatments, including the purchase of home equipment, require a prescription from your doctor.

  • Psoralen + UVA (PUVA)

Unless combined with light-sensitizing drugs such as psoralens, ultraviolet light A (UVA) is generally inefficient for psoriasis. This procedure, known as PUVA, reduces excessive skin cell proliferation and can temporarily relieve psoriasis symptoms. PUVA can be administered in three ways: topically as a cream, added into bathwater, or taken orally. PUVA therapy is particularly effective for stable plaque psoriasis, guttate psoriasis, and psoriasis of the palms and soles.

  • Sunlight

Although both UVB and UVA are present in sunshine, UVB is more effective for psoriasis. UVB from the sun functions similarly to UVB from phototherapy treatments. However, treating psoriasis with sunshine is not for everyone. Sunlight is not as effective as prescription phototherapy in treating psoriasis. Consult your doctor to see whether treatment with sunlight is appropriate for you.

Some topical treatments might increase your chances of getting sunburned. Tazarotene and coal tar are two examples. Before going out in the sun, those who use these products should consult with their doctor. Unless told otherwise by a health care physician, people who use PUVA or other kinds of light treatment should minimize or prevent exposure to natural sunshine.

There are a few specialized forms of phototherapy, such as lasers, photodynamic therapy (PDT), bath-PUVA, and extracorporeal photochemotherapy. Phototherapy is still the most commonly used treatment modality for a variety of skin diseases, such as parapsoriasis, psoriasis, pityriasis lichenoides chronica, eczema, atopic dermatitis, vitiligo, photodermatitis, polymorphous light eruption, actinic prurigo, hydroa vacciniforme, cutaneous porphyrias, Mycosis fun

UVB phototherapy has anti-inflammatory, immunosuppressive, and cytotoxic effects. The methods of action are unknown, although they include the production of cis-urocanic acid, the depletion of Langerhans cells, altered antigen presentation, reduced activity of natural killer (NK) cells, and T lymphocyte and keratinocyte death.

PUVA's modes of action include DNA cross-linking via psoralen photoadducts, DNA replication inhibition, Langerhans cell depletion, and immunosuppressive effects on T-lymphocyte function and migration. UVA-1 phototherapy penetrates deeper into the dermis and stimulates interstitial collagenase and cytokines, easing sclerotic skin. Dendritic cells acquire antigen from apoptotic lymphocytes, eliciting a particular immune response without inducing widespread immunosuppression.




Jaundice is the yellow hue of the skin caused by bilirubin accumulation in the dermal and subcutaneous tissue. Bilirubin is normally metabolized by the liver, where it is converted to glucuronic acid by the enzyme uridine diphosphate glucuronyl transferase (UGT). This conjugated bilirubin is subsequently excreted into the bile and eliminated from the body through the stomach. When this elimination mechanism is inefficient or overwhelmed by the quantity of endogenously generated bilirubin, the amount of bilirubin in the body rises, resulting in hyperbilirubinemia and jaundice.

Jaundice affects up to 60% of all normal babies within the first week of life. A newborn's jaundice can be caused by an underlying medical disease, such as isoimmune hemolysis or an RBC enzyme deficiency. However, it is most usually owing to the newborn infant's typical physiological failure to absorb bilirubin effectively as a result of the combined effects of higher RBC turnover and a transitory deficiency in bilirubin conjugation in the liver. This form of nonpathologic jaundice is known as neonatal physiologic jaundice.

Bilirubin concentrations in most newborns with physiologic jaundice do not increase to the point where therapy is required. However, bilirubin in the blood reaches very high amounts in some children with excessive physiologic jaundice and in many infants with pathologic jaundice, putting the infant at risk for acute and chronic bilirubin encephalopathy (kernicterus). To avoid kernicterus, medication targeted at reducing bilirubin concentration is essential in these situations.


What should I expect with phototherapy?


During your appointment, you will apply a moisturizing oil to your skin and stand naked in a huge cabinet save for underpants and goggles to protect your eyes. The light-emitting equipment will be triggered for a brief period of time - often seconds to minutes - and will either treat the entire body or specific exposed parts. It may take one or two months of consistent phototherapy treatment to begin to show improvement in eczema symptoms, at which point the number of visits can occasionally be reduced or discontinued for a period of time to assess if the eczema is in remission.

Potential side effects of phototherapy include:

  • Sunburn and skin tenderness (common)
  • Premature skin aging (common)
  • Photosensitive skin eruptions
  • Nonmelanoma skin cancer
  • Cataracts (from UVA treatment)


Why does dosage constantly change during phototherapy?

NB-UVB radiation

During phototherapy, your skin quickly adapts to the amount of NB-UVB radiation given. To maintain healing, the dose of light provided to specified regions must be gradually raised based on your skin's reaction to therapy. Because everyone reacts differently to phototherapy, and various parts of the body react differently, therapists rely on patients' self-assessment of their skin the day following a light treatment.

Personalized instruction and thorough inspection of your images assist you in determining if your light dose (the amount of time you treat a specific region) should be increased, decreased, or maintained. Based on your doctor's prescription, the Clarify System automatically estimates the length of time the NB-UVB is supplied.


Why does dosage constantly change during phototherapy?

During phototherapy, your skin quickly becomes accustomed to the dose of NB-UVB energy delivered. In order for healing to continue, the dose of light delivered to targeted areas must be continually increased, depending on your skin's response to therapy. Since everyone responds differently to phototherapy, and different areas of the body respond differently, clinicians depend on patients' self-assessment of their skin the day after a light treatment is delivered. 


How often is phototherapy needed?

Phototherapy treatments are usually given three times a week. Significant improvement in psoriasis may be evident within two weeks. Most persons with psoriasis may require 15 to 20 treatments to achieve clearance, with a remission rate of 38% after one year. Phototherapy treatment for vitiligo patients is more complicated. The pace of repigmentation is affected by the amount of time you have had vitiligo, the body areas you wish to treat, and the activity of your vitiligo.

Those who started therapy within two years of their diagnosis, treat the face and neck, and have stable, unchanging vitiligo with no symptoms of activity had the best chance of responding. Those with active vitiligo require more intensive treatment, which may include full-body phototherapy and oral steroids. 


Is phototherapy safe?

phototherapy risks

Dermatologists believe that when used appropriately, NB-UVB light treatment is safe. A higher incidence of skin cancer has not been demonstrated in the few human researches that have looked into this issue. There was no significant relationship with basal cell carcinoma, squamous cell carcinoma, or melanoma in the biggest trial to date, which included 3867 psoriasis patients treated with NB-UVB, with the median number of treatments being 29 and 352 patients having more than 100 treatments. The average length of follow-up was 5.5 years.

However, greater research on what happens after that span is required. Furthermore, newer, more specialized kinds of phototherapy, such as the Clarify System, have recently been created. Targeted treatment is intended to direct therapeutic light to the damaged area while avoiding unneeded light exposure to adjacent skin.

Healing can occur sooner with current breakthroughs in photomedicine and when used in conjunction with other treatments, reducing overall UV exposure. UVA rays from the sun and tanning beds can harm the deeper layers of your skin. 

Experts concur that there is most certainly a link between NB-UVB and the development of nonmelanoma skin cancer. As a result, in the United States and many other countries, a prescription for these therapies is needed by law. So, before you use a phototherapy treatment, you should discuss all of the benefits and potential side effects. You and your doctor can make an informed decision together.


What happens after my skin clears?

Maintenance therapy

When you attain your skin healing objectives, your doctor will likely suggest maintenance therapy. Maintenance therapy is a strategy for reducing the treatment dose or frequency. The objective is to extend your period in remission, or time without your skin problem.

If your immune system remains hyperactive or becomes overactive in the future, for example, if it is provoked by stress, sickness, trauma, delivery, or other unforeseen or unknown causes, more active therapy may be required. In this case, the dose and frequency of light therapy are generally increased.

If you observe any changes in your condition, it's critical that you address them with your doctor as soon as possible so that you can choose the best course of action to treat your skin.


Phototherapy Complications

Phototherapy Complications

After arriving home, contact your doctor if any of the following occurs:

  • Signs of infection, including fever and chills
  • Redness around the skin lesions or any discharge
  • Severe skin burning, pain or blistering
  • Side affects you experienced due to the treatment continue or worsen
  • Development of new symptoms

In case of an emergency, call for medical help right away.

  • Phototherapy Risks

The UV lights may negatively affect your skin in a number of ways, including:

    • Skin conditions could temporarily worsen
    • Itchy skin
    • Red skin due to exposure to the lights
    • Burning of the skin

PUVA treatment may also cause:

  • Nausea
  • Burning skin
  • Cataracts — lens of eye becomes cloudy, affecting vision
  • Headache
  • Fatigue

If you have received a great number of phototherapy treatments, you may be at risk for:

  • Premature aging of the skin, such as wrinkling and dryness
  • Age spots or freckles

Factors that may increase the risk of complications include:

  • Allergy to sunlight
  • Pregnancy or nursing
  • Medical conditions, such as skin cancer or lupus, that require you to avoid the sun
  • History of skin cancer
  • Liver disease — phototherapy may increase medication levels in the blood




There is still hope if you have a skin problem that does not respond to traditional therapies. Phototherapy can successfully cure several inflammatory skin conditions. Phototherapy is a safe, simple, and effective treatment method for a variety of dermatoses that is inexpensive in cost and has fewer adverse effects. 

Because the disease burden of dermatological diseases is high, phototherapy has a superior efficacy in treating patients with psoriasis, mycosis fungicides, atopic dermatitis, pityriasis Versicolor, chronic urticaria, palmoplantar pustulosis, and vitiligo when compared to topical or systemic therapy. Because phototherapy is a safe alternative to systemic therapy, it protects patients from the negative effects of systemic therapy.