Mechanism and dose selection of narrow-spectrum UVB in the treatment of psoriasis, vitiligo and other diseases

Type:Uv phototherapy   Time:2018-09-06 10:40:52
Introduction to 311nm UVB (Narrow Spectrum UVB):
¡ñ In recent years, it has been found that UVB at <295 nm has no anti-psoriatic effect and is prone to erythema reaction. The UVB of 300¡«313nm can alleviate psoriasis, and clinical practice shows that the efficacy of 311nm UVB is better than that of broad-spectrum UVB. The incidence of erythema reaction is low, and the disease remission time is long. The effect is similar to PUVA, but there is no need to take photosensitivity. The agent has low cost and can be used for pregnant women and children, and has the advantages of small carcinogenicity. At present, the application in Europe is relatively wide, and the application in the United States is gradually increasing. Many hospitals in China have begun to treat psoriasis using 311-312 nm narrowband UVB.
¡ñ Narrowband UVB (narrowband UVB TL01) has the best anti-psoriatic activity and is superior to traditional broad-spectrum UVB light therapy in cleaning and recovery time. Narrow-spectrum UVB has been successfully applied to a variety of combination therapies such as RePUVA, anthralin, calcipotriol. Its anti-psoriatic effect is the future development and direction. The use of drugs and combination therapies is designed to increase efficacy and reduce the cumulative amount of UVB to reduce the risk of long-term side effects. Do not topical combination of steroids because it will result in a shorter recovery period.
¡ñ In the treatment of psoriasis, from our research and other reports, narrow-spectrum light therapy has similar effects to PUVA. The therapeutic effect is directly proportional to the formation of erythema, but excessive erythema is limited in light therapy. The erythema dose is also related to the therapeutic effect in the UVA spectral range, but the required dose is hundreds of times higher than UVB phototherapy. In fact, UVA treatment is no better than UVB.
¡ñ Application (NB-UVB TL01) 311nm UVB treatment of vitiligo is more effective than PUVA therapy, faster pigment regeneration, less phototoxicity, skin itching and dry skin. After long-term radiation, no visible keratosis of the epidermis was observed in the damaged skin, and the cumulative radiation dose was small and the time for each treatment was short.

¡ñ Light source: narrow spectrum UVB (narrowband UVB TL01, NB-UVB):
Wavelength range: 310 to 315 nm, peak: 311 nm.
¡ñ Based on skin typing, experience to determine the first dose:
skin
Type
Skin characteristics
Narrow-spectrum UVB
TL 01J/cm2
Wide spectrum UVB
J/cm2
I
It is always easy to get sunburned and not tan.
0.2-0.3
0.01-0.02
II
It is always easy to get sunburn and sometimes tanning.
0.2-0.3
0.01-0.02
III
Sometimes sunburn, always tan.
0.3-0.5
0.02-0.03
IV
The bushes are not sunburned and always tan.
0.5-0.7
0.02-0.03
V
Moderate pigmentation
0.5-0.7
0.03-0.04
VI
black
0.5-0.9
0.04-0.05

Follow-up treatment dose adjustment principles:
¡ñ In the initial stage of treatment, in the case of avoiding adverse reactions, the use of larger doses has a better effect.
(Get the best treatment dose as soon as possible in the early stages of treatment)
¡ñ Under the premise of ensuring good curative effect, use a smaller dose to avoid possible adverse side effects after long-term treatment.
(late treatment with a smaller dose later)
A. There is no erythema effect or
The previous light erythema effect disappeared
Increase the dose by 20-25% each time.
B. Slight erythema effect
With the last dose or increase of 10% dose, the erythema effect disappeared after the same A.
C. Asymptomatic, clear and arguable
erythema
Stop treatment once, then illuminate with the same dose, and gradually increase the dose by 10% each time.
D. Painful erythema, or with edema, blisters
Stop treatment until recovery. Reduce the dose by half and increase the dose by 10% each time.
¡ñ Psoriasis:
3 to 4 times a week, 15 to 20 times / course of treatment. A cleansing session can be added after the patient's condition improves.
3/w¡Átwo weeks, 2/w¡Átwo weeks, 1/w¡Átwo weeks, 2/M¡Áone month, follow-up.
¡ñ Vitiligo:
2 to 3 times a week, 30 to 50 times or more treatments are required.

¡ñ Rose pityriasis:
UVA/NB-UVB 5~6 times
¡ñ Parapsoriasis, MF:
PUVA, UVA/UVB, NB-UVB, 4/w, to histology improved, 2/w ¡Á one month,
1/w ¡Á one month, follow-up.
Treatment options for specific diseases:
A, psoriasis:
Narrowband UVB (narrowband UVB 311nm) for the treatment of psoriasis:

In recent years, it has been found that UVB at <295 nm has no anti-psoriatic effect and causes an obvious erythema reaction. The UVB of 300-313 nm has the best anti-psoriatic activity, which can alleviate psoriasis. And clinical practice shows that 311nm UVB is better than broad-spectrum UVB, the incidence of erythema reaction is low, the disease is relieved for a long time, the effect is similar to PUVA, but it does not need to take medicine, the cost is low, it can be used for pregnant women and children, and the carcinogenicity is small. The minimum phototoxicity was determined before treatment, and the amount of matt toxic was used as the initial irradiation amount. Irradiate once every other day, 15-20 times for a course of treatment. At present, the application in Europe is relatively wide, and the application in the United States is gradually increasing. Many hospitals in China have begun to use 311 ~ 312nm narrow-spectrum UVB to treat psoriasis.
The total effective rate is over 95%
Treatment: Narrow-band UVB (narrowband UVB 311nm) treatment, 3 times / week, 20 treatments continue to use consolidation therapy.

B, vitiligo:
Vitiligo is a pigmentation loss spot caused by a decrease or loss of skin melanocytes. Irradiation was induced by photochemotherapy (drug 8-oxo-psoralen plus UVA) or narrow-spectrum UVB (311 nm) to promote melanin formation. The minimum phototoxicity was measured before treatment, and the amount of matt toxic was used as the initial exposure, 2-3 times per week. Need to adhere to treatment, usually need 30-50 times or more treatment. In particular, it shows a good effect on facial rash. For the trunk and limb rash, the effect is poor and may require a longer course of treatment. This therapy has good safety and tolerability. There is no significant effect on normal skin.
The total effective rate is over 80%.
Treatment: treatment with narrow-spectrum UVB (narrowband UVB 311nm), 2-3 times / week. It takes a long time (40-60 times) to treat, and the maximum therapeutic dose is controlled at 2.5-3.0 J/cm2.

C, rose pityria:
Pityriasis rosea is a common self-limiting inflammatory skin disease. The onset may be related to viral infection, using physical therapy that is ultraviolet (UVA or narrow-spectrum UVB), with sub- erythema, once every other day, 10 times for a course of treatment.
The total effective rate is over 95%.

D, refractory atopic dermatitis:
The treatment was performed with narrow-spectrum UVB TL01 (311 nm) light, and the dose of sub-erythema was used as the initial dose, which was increased by about 20% each time until the light red spot appeared, and the dose was maintained three times a week, 15-25 times for one course of treatment.
The total effective rate is over 60%.

E, severe seborrheic dermatitis:
Seborrheic dermatitis is a very common papular scaly skin disease, which accounts for 2 to 10% of the adult population. The current treatment methods are limited and the curative effect is not good. The treatment was performed with narrow-spectrum UVB TL01 (311 nm) light, and the dose of sub-erythema was used as the initial dose, which was increased by about 20% each time until the light red spot appeared, and the dose was maintained three times a week for 8 weeks.
The total effective rate is over 90%.

F, vice psoriasis:
Parapsoriasis, a group of chronic skin diseases of unknown etiology, characterized by erythema, papules, infiltration, and scales without symptoms. Alternate irradiation with photochemotherapy (PUVA) or UVB irradiation or UVB and UVA can be used. Apply a mild lubricant to the outside before irradiation. 10-20 times for a course of treatment.

G, MF and palmoplantar pustulosis:
MF and palmoplantar pustulosis have a long course of disease, self-limiting, no special drugs to treat, the use of phototherapy treatment is good, can reduce or not use immunosuppressants. Palmoplantar pustulosis is effective 4 to 5 times. MF works quickly, but it takes a long time to consolidate. The increase in the dose of both diseases is the same as psoriasis.

H, other:
Narrow-spectrum UVB irradiation or UVA and UVB mixed irradiation also has a good effect on atopic dermatitis, eczema, herpes zoster, and postherpetic neuralgia.

Adverse reactions and treatment of narrow-spectrum UVB phototherapy:

¡ñ Recent adverse reactions: including erythema, dry pruritus, occasional photodamage of blisters, and periodic herpes simplex with increasing frequency.
Subacute effects such as pruritus and dry skin, apply a gentle skin lubricant after a cold bath.
¡ñ Moderate painful erythema caused by excessive exposure.
Topical application of corticosteroids.
¡ñ Long-term adverse reactions: the possibility of photoaging and carcinogenesis. The relationship between UVB phototherapy and non-melanoma skin cancer has not been found in the current study.

side effects:
¡ñ The skin is dry.
¡ñ Itching and stinging.
¡ñ erythema reaction.
¡ñ Excessive exposure

Treatment method for excessive light:
¡ñ When an excessive amount (irradiation time exceeds the specified time) is detected immediately after the irradiation, the infrared ray or the local warm water bath can be irradiated immediately, and the subsequent reaction can be alleviated.
¡ñ If the erythema has appeared, it is found that the dose is too large (reaction exceeds the expected dosage level) corticosteroid cream or 2.5% indomethacin cream. The former has anti-inflammatory effects to reduce redness and swelling. The latter inhibits prostaglandin synthetase and reduces the concentration of prostaglandins, the main mediator of erythema, thereby exerting an anti-inflammatory effect.
Treatment with mild light overdose:
¡ñ It is best to rinse with hot water or hot water bath immediately after irradiation for about 30 minutes. Oral anti-histamines such as chlorpheniramine, etc., together with topical corticosteroid cream, can reduce redness and swelling after skin light. .
Treatment method for heavy excessive light:
¡ñ Hot water rinse (hot water bath soak) or infrared light bath:
Partial or whole body light baths can be selected and the temperature in the light bath must not exceed 45 ¡ãC. Irradiation for about 30 minutes can alleviate or reduce redness and blisters. Attention should be paid to covering the eyes with gauze during the treatment to prevent eye damage.
¡ñ Systemic treatment:
Immediately muscle or intravenous dexamethasone 5-10mg, oral antihistamines.
¡ñ Local treatment:
The skin has been red and swollen, and it can be wet-coated with 3% boric acid solution, 2-3 times a day for 15-20 minutes or continuous wet application. Topical corticosteroid ointment Yuzhul, skin relax, Ai Luosong and so on.
¡ñ If blister bullae appear, you can follow the scald treatment and take out the blister to keep the skin clean and dry.