Phototherapy (narrow band UVB therapy etc)

Some of the patients who are reading my blog may have experience of phototherapy.
It is not a bad idea. Ultraviolet rays can suppress the eczema in certain patients. There is no report of rebound after phototherapy like TSA.
However, there are a few problems which tend to be overlooked. One of them is about the amount of light.

For example, there is a portable device for NB-UVB phototherapy like the below.

According to the manual, you use this apparatus like this (almost contacting directly to the skin).

How much is the amount of the light? You can measure it by yourself. No, you should measure it rather than you can.

You could find a measuring instrument on website and purchase it. It is not so expensive. For example, one in the below photo costs JPN 1,490 (= USD 15).

 

 Let’s try to measure it.

The value was 2.3W/m2.

 Theoretically, UVB therapy should be performed after the measurement of MED (minimal erythema dose) of each patient. It is because the reaction to ultraviolet rays differs by patient. Averagely it is 0.75J/cm2 in UVB. You are to start from one half or two third of the MED dose usually.

 An example of MED measurement

You need to convert W/m2 to J/cm2. The amount of light (J/cm2) is the product of the intensity (W/m2) and time (minute). I made a useful sheet as the below. When the intensity is 2.3W/m2, the time required to obtain 0.75J/cm2 is about 54min.

It must be difficult to treat the whole body by this small apparatus. I think the most reasonable usage of this apparatus is a challenge test to determine if phototherapy works to your eczema. You can treat a small area by irradiating every day for 10 minutes for example. The accumulated sum of the amount of light should be recorded as I write in the followings. 

In clinics or hospitals there are larger and stronger apparatus. However, remember that sometimes the dose (amount of light) is not enough because some doctors are afraid of accidental iatrogenic burning. Doctors have various policies. Some prefer scientific approach by measuring the intensity of the apparatus while others prefer riskless and empirical approach starting from very low dose and then increasing gradually. Under the latter doctors, patients might misunderstand that phototherapy is not useful.

So I believe patients had better purchase their own UVB checker and measure the intensity by themselves. The intensity depends on the distance from the apparatus. Also it depends on the age of light bulb. Even if the apparatus is large, the amount of light is not always enough because it depends on the distance, light bulb age and irradiation time.

The eczema may subside according to the accumulated dose. The dose for efficacy differs by patient. What is obvious is that you are not to be cured if the dose is too small. You should record the dose of every treatment, calculate the sum and compare it with the severity of eczema by yourself.

There are other methods than NB-UVB in phototherapy. They are the eximer laser and the UVA1. The result by eximer laser varies less than NB-UVB because the distance from the handpiece is fixed.

 Eximer laser treatment

There are several articles suggesting that phototherapy could help the recovery from TSA. For example, in the following article, Eximer laser is reported to be more useful for subsiding prurigo type of atopic dermatitis than topical steroids. As I have already written, prurigo type is often accompanied by TSA and hard to be treated by TS.
   
Excimer laser vs. clobetasol propionate 0•05% ointment in prurigo form of atopic dermatitis: a randomized controlled trial, a pilot. Brenninkmeijer EE,et al. Br J Dermatol. 2010 Oct;163(4):823-31.
   
On the other hand, there is another way to confirm if your eczema reacts to phototherapy. It is a travel to the area where natural UVB by sunlight is strong. For example, the intensity in Hawaii at noon in May is about 545 microW/cm2 (=5.45W/m2).
http://pets.groups.yahoo.com/group/UVB_Meter_Owners/message/3615

It is nonsense for patients living in Hawaii to use the above handy apparatus. They can be exposed to over the twice more intensity of UVB by only taking a walk outside.

I remember my journey to Sri-Lanka when I was young. As I was interested in UVB in the countries right on the equator I carried my UVB checker with me and measured. I couldn’t measure it because the intensity was over the upper limit of the apparatus.

There were patients with atopic dermatitis also in Sri-Lanka. It means phototherapy doesn’t always work for all patients.

I have some friendly doctors in Russia. One of them asked me once if I could send a certain sunscreen cosmetics made in Japan which was available in Russia at that time. She thought it must be more reasonable if I purchased it in Japan and sent it to her.

I have never seen the sunscreen in Japan but the manufacturer was a famous Japanese company. As I had a friend in that cosmetics company, I asked if there was any product of the similar ingredients.

He said, “Doc, this sunscreen is really a product of our company. It is made in Thailand and directly exported to Russia. So it is not available in Japan.”

“It’s OK. But if it is a product of your company, there must be a similar product. My friend will be satisfied with it.”

“Sorry to say, we don’t have a similar product in Japan.”

“Why?”

“In fact the product contains no ultraviolet-protective ingredient. There are very little ultraviolet rays in Russia. So our company doesn’t add any ultraviolet-protective agent to the sunscreen. What is written as a sunscreen is no more than imaging up. Maybe such an expression is not illegal in Russia differently from in Japan”

This is an episode of digression. But I think that Russian patients with eczema have a greater possibility of improvement by phototherapy than patients in Sri-Lanka.

This is a sign board of my clinic on the top of the building. As I am now a cosmetic surgeon, I must protect my clients from aging by ultraviolet rays. So I am selling sunscreens containing true ultraviolet-protective agents in my clinic and indicating UVA intensity on the sign board in real time for enlightening.
But I know ultraviolet rays have an aspect of good efficacy to the skin also.

There is no medication without side effects. TSA is a terrible side effect of TS but TS has a useful aspect also.  It is just like human beings. Any good person has some defects while any bad person has a few good aspects too. Nothing is absolutely bad or good.

Sorry, the comment column is not available now. But the author believes readers can find some hints to overcome their own situations by the previous comments.