Bath PUVA and Psoriasis: Is a Milder Treatment a Worse Treatment?

Type:Uv phototherapy   Time:2017-02-09 14:12:07

Introduction

 

Topical application of psoralens followed by UVA ir-radiation (PUVA) has been used in the treatment of pso-riasis. Bath PUVA is a form of PUVA administration in which psoralen is applied to the skin by bathing in a di-lute aqueous solution, instead of administering psoralen to the skin from systemic dosing. The treatment schedule for topical PUVA has not yet been standardized. The aim of our study is to evaluate milder UVA dosages for bath PUVA, regardless of phototype. Although erythema is the limiting factor related to the UVA dose that can be given at each treatment, erythemal sensitivity in PUVA bath therapy, measured as minimal phototoxicity dose (MPD), is not correlated with the sun-reactive skin pho-totype in skin types II and III. Thus, skin phototype is not a suitable indicator for the initial UVA dose in PUVA bath photochemotherapy [1].

Methods

 

In the Dermatologic Clinic of Oriental Piedmont, bath PUVA had always been performed according to the European protocol. Over 1 year, we enrolled 30 patients with chronic plaque-type pso-riasis, who were divided into 2 groups (group 1: n = 10, group 2: n = 20). All the patients were informed about the risks and the duration of the therapy and signed a detailed informed consent form. The starting Psoriasis Area and Severity Index (PASI) scores were not significantly different between the groups (table 1).

 

Patients bathed (bathing time 20 min) in 150 litres water (37 ∼ C) in which 8-methoxypsoralen (8-MOP) was dissolved to a final concentration of 0.3 mg/dl.

Group 1 was treated with the starting dose and the dose pro-gression recommended by guidelines of the British Photoderma-tology Group for bath PUVA [2]. Treatment was given 3 times per week. The starting dose was 0.5 J/cm 2, which went up to 8 J/cm2 每 the maximum dose.

 

Group 2 was treated by using a lower first dose, a slower dose progression and a lower maximum dose. Four treatments were given per week during the first month. They were scheduled on 2 consecutive days, followed by a rest day, and then the next 2 treatment days, with increasing UVA doses until the patients showed erythema or a sufficient improvement of their disease. Three treatments were performed each week in the second month, and 2 each week in the third. The dose increment was fixed at 0.25 J/cm2 twice a week. The starting dose was 0.20 J/cm 2, and the maximum dose was 4.5 J/cm2. During therapy, no application of moisturizers or other topical treatment was allowed. Although in the first month the number of treatments is higher for group 1, at the end of the third month the total number of treatments per-formed (36) is the same for both groups.

 

The outcome measure was the PASI score, assessed initially and every month until the end of the treatment.

Results

 

In group 1, the median baseline PASI score decreased from 15.2 to 4.5 (p ! 0.005, Student＊s paired t test), while in group 2 it decreased from 13.7 to 4.1 (p ! 0.005). No statistical difference between the groups was detectable. Severe phototoxic reactions such as strong erythema, blistering and/or pain were observed only in 2 patients of

Table 1. Patients included in the study

 

 

Skin

Gender

Age

Duration

PASI

 

type

 

 

years

of psoriasis

score

 

male

female

 

 

 

years

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Group 1

II每III

7

3

43.2

7.282

15.282.5

Group 2

II每III

11

9

45.9

6.184.6

13.784.1

 

 

 

 

 

 

 

 

 

 

group 1. Side effects were not observed in group 2. Com-pliance of the patients to the treatment was optimal, and the number of missed therapeutic sessions was negliga-ble.

 

The mean cumulative dose for the first group was 145 J/cm2 (820.5), while for the second it was 86 J/cm2 (86.5). The PASI score slope is displayed in figure 1.

 

 

Discussion

 

Until 2000 there were no protocols for topical PUVA accepted worldwide, and the therapeutic schedule was derived from oral PUVA protocols, which recommended 4 treatments per week on 2 consecutive days followed by a rest day and then the next 2 daily doses. Increments were given only after the first week and range from 0.5 to 2 J/cm2. The specific US and European protocols are as follows.

 

US Protocol

 

In the absence of controlled trials, American derma-tologists mostly apply the same principles to bath PUVA as to oral PUVA, based on the United States Cooperative Clinical Trial (USCCT) protocol [3].

 

The first treatment exposure dose is based on the skin type, and the patients are treated either 2 or 3 times a week. Dose increments range from 0.5 to 1.5 J/cm 2, de-pending on erythema production and therapeutic re-sponse.

 

European Protocol [2]

 

MPD has to be determined before giving the first dose. Directions for treatment are:

 

每 dissolve 30 ml of 1.2% 8-MOP lotion in 140 litres of water at 37 ∼ C;

 

每 bathe for 15 min, followed by immediate UVA expo-sure;

 

每 initial UVA dose: either 40% of MPD (preferable) or 0.2 8 0.5 J/cm2;

每 UVA increments: increase by 20 840% of initial dose at each treatment;

 

每  frequency: twice weekly.

 

In our experience 4 treatments in the first month, the

 

critical period for clinical response and side effects, en-sure that the physician has a better follow-up of the pa-tient. According to our data, it is possible to decrease the UVA mean cumulative dose while obtaining the same therapeutic result, through increasing the number of treatments in the first month.

 

The risk of non-melanoma skin cancer, following mul-tiple treatments with oral PUVA, is now recognized [4]. Advantages of topical psoralen therapy are that systemic side effects, such as nausea, and hazards, such as carcino-genic effects, can be avoided [5, 6]. No equivalent data exist for topical PUVA. Also, the duration of remission after successful therapy is significantly longer for bath PUVA when compared to oral PUVA and UVB treat-ments [7].

Conclusions

 

Efficacy, tolerability and safety of bath PUVA in the treatment of psoriasis were already widely known, and there is a large consensus among dermatologists about the usefulness of photochemotherapy [8]. Furthermore, from our data, it is possible to decrease the mean cumula-tive UVA dose, whilst still reaching the same therapeutic result. Our investigation can be considered as a pilot study, indicating that a larger randomized study is re-quired to determine changes to the guidelines of the Brit-ish Photodermatology Group for bath PUVA, specifically changes which decrease the mean cumulative UVA dose. In fact, although theoretically, there is a very low carci-nogenic risk for bath PUVA, there are no long-term fol-low-up studies for this method, and there is currently in-sufficient evidence to conclude that this treatment is to-tally safe [2].

 

To conclude, a milder, prudent therapeutic approach seems to be a more effective, tolerable and safer way of achieving the same results as the more aggressive ap-proaches.