Psoralen cream plus ultraviolet A photochemotherapy (PUVA cream): our experience

BACKGROUND: Psoralen ultraviolet A (PUVA) bath photochemotherapy has been proved highly effective in the treatment of various dermatoses without potential side-effects of systemic therapy. Another form of topical PUVA therapy (PUVA cream) without the logistical requirements for bath tubs has recently been developed. OBJECTIVE: We sought to develop preparation and treatment standards to PUVA cream and to confirm its clinical efficacy in the treatment of various dermatoses. METHODS: In the first phase, the safety of a novel cream containing 0.002% 8-methoxypsoralen (8-MOP) was determined in six healthy volunteers. In a second phase, 40 patients with different dermatoses were treated with a minor concentration (0.001% 8-MOP), following the guidelines for topical PUVA of the British Photodermatology Group. RESULTS: Plasma levels of psoralen after the application of the novel cream containing 0.002% 8-MOP, were less than 34 ng/mL, the maximum 8-MOP concentration reported for topical PUVA. With a minor concentration (0.001% 8-MOP), important improvement or healing was found in 53.3% of the cycles, generally with a good response since the first month of treatment. Only mild side-effects were detected in 14 patients. CONCLUSIONS: Based on our data, PUVA cream photochemotherapy is well accepted by patients and may be a highly effective treatment even if previous therapy was unsuccessful. In addition, PUVA cream is easier to use than PUVA bath.     

Treatment of necrobiosis lipoidica with topical psoralen plus ultraviolet A

BACKGROUND: Necrobiosis lipoidica (NL) is a rare skin disease, mostly seen on the legs and often occurring in patients with diabetes mellitus. The disease belongs to the idiopathic cutaneous palisading granulomatous dermatitides associated with a degeneration of collagen, thus leading to skin atrophy. Application of topical corticosteroids is the most widely used treatment but the results are not always satisfactory and may worsen skin atrophy. Preliminary studies in patients with NL have shown a clinical response with psoralen plus ultraviolet (UV) A (PUVA). Objectives To study the effect of topical PUVA on NL in a multicentre prospective study. METHODS: Thirty patients (27 women and three men) including 13 with insulin-dependent diabetes mellitus, with a diagnosis of NL proven by histopathology, were included. All patients had been unsuccessfully treated with topical and/or intralesional corticosteroids. Patients were treated twice weekly with an aqueous gel containing 0.005% psoralen followed by irradiation with UVA. Clinical photographs were taken for evaluation. In addition, 20-MHz high-frequency ultrasound analysis was performed in 10 patients to evaluate the thickness and density of the dermis during topical PUVA therapy. RESULTS: Five patients (17%) showed complete clearing (healing of ulceration and disappearance of erythema) after a mean of 22 exposures (range 15-30). Eleven patients (37%) showed improvement, defined as healing of ulceration and/or reduction of erythema, after a mean of 23 exposures (range 11-42). Ten patients (33%) showed no effect and four patients (13%) worsened during topical PUVA therapy. The treatment results of the patients who suffered from diabetes mellitus were not different from those who did not have diabetes mellitus. No difference was seen in mean dermal thickness (1666 vs. 1706 micro m) and density (17 vs. 16 units) before and after topical PUVA therapy. Side-effects were seen in 10 patients: hyperpigmentation (n = 4), blistering (n = 4) and bacterial infection (n = 2). CONCLUSIONS: Topical PUVA may be a useful treatment modality for NL in patients not responding to topical or intralesional corticosteroids.     

Cream psoralen plus ultraviolet A therapy for granuloma annulare

BACKGROUND: Treatment modalities for granuloma annulare (GA) often remain unsatisfactory or can be accompanied by potentially hazardous side-effects. Psoralen plus ultraviolet (UV) A (PUVA) bath photochemotherapy has been reported to be highly effective in the treatment of GA. Another form of topical PUVA therapy, using 8-methoxypsoralen-containing cream or gel preparations, has been proven to be as effective as bath PUVA therapy in the treatment of palmoplantar dermatoses. OBJECTIVES: To assess the efficacy of cream PUVA photochemotherapy in patients with GA. METHODS: Five patients with GA were treated. The diagnosis was confirmed by pretreatment skin biopsies. Cream PUVA therapy was performed four times a week: the mean number of treatments was 26 (range 17-40) and mean cumulative UVA dose was 55.9 J cm-2 (range 18.2-109.2). RESULTS: Cream PUVA photochemotherapy induced significant clinical improvement (one patient) or clearance (four patients) of GA in all patients. Clearance was documented clinically and histopathologically. CONCLUSIONS: Cream PUVA phototherapy can be highly effective in patients affected by localized forms of GA.     

Eosinophilic fasciitis treated with psoralen-ultraviolet A bath photochemotherapy

Eosinophilic fasciitis is a rare disorder which can markedly affect the quality of life in individual patients. So far, no generally accepted and effective treatment modality has been available. Although the precise nature of eosinophilic fasciitis is still unknown, it is often regarded as a variant of localized scleroderma (morphoea). Phototherapy and photochemotherapy have been shown to be effective in the treatment of sclerodermatous skin lesions. We report a patient with eosinophilic fasciitis which was successfully treated with psoralen plus ultraviolet A bath photochemotherapy within 6 months.     

Topical calcipotriol as monotherapy and in combination with psoralen plus ultraviolet A in the treatment of vitiligo

BACKGROUND: Recent advances in the pathophysiology of vitiligo have demonstrated defective calcium homeostasis in depigmented skin. 1,25-Dihydroxyvitamin D3 may be involved in the regulation of melanin synthesis, and receptors for 1,25-dihydroxyvitamin D3 have been demonstrated on melanocytes. OBJECTIVES: We conducted an open study to determine the efficacy and tolerability of calcipotriol cream as monotherapy and in conjunction with psoralen plus ultraviolet A (PUVA) in the treatment of vitiligo. METHODS: Twenty-six patients with vitiligo affecting 5-40% of their skin were recruited. Twenty-two were treated with twice-daily topical calcipotriol monotherapy (50 microg g(-1)) and four were placed on combination treatment with twice-daily topical calcipotriol 50 microg g(-1) in conjunction with topical or oral 8-methoxypsoralen PUVA three times weekly. RESULTS: Treatment was well tolerated at all sites and no adverse effects were reported. After a therapy time of 3-9 months (mean 6 months), 77% (17 of 22) of those treated with monotherapy showed 30-100% improvement, and three of the four patients on combination treatment showed good response. CONCLUSIONS: Topical calcipotriol appears to be an effective and well-tolerated treatment for vitiligo and can be safely used in conjunction with PUVA, but controlled studies are necessary to exclude the possibility of spontaneous repigmentation.     

Effects of psoralen plus ultraviolet A irradiation on cultured epidermal cells in vitro and patients with vitiligo in vivo

BACKGROUND: Both psoralen plus ultraviolet (UV) A (PUVA) and narrowband UVB (NB-UVB) irradiation are effective treatments for vitiligo vulgaris. However, the mechanisms of PUVA and NB-UVB in repigmentation are not thoroughly clarified. Our previous results showed that NB-UVB irradiation directly promotes melanocyte (MC) migration and stimulates MC proliferation via keratinocytes (KCs). OBJECTIVES: In the present study, we used NB-UVB as a reference for comparison to investigate the immediate effects of PUVA on MC proliferation and migration. METHODS: Cultured MCs and KCs were treated with PUVA or irradiated with NB-UVB. The direct impact of PUVA treatment on MCs was assessed in terms of its effect on MC proliferation and migration. The indirect effect of PUVA treatment and NB-UVB irradiation on MC proliferation via KCs was also investigated. The activities of matrix metalloproteinase (MMP)-2 and MMP-9, known for their influence on cell migration, were evaluated in the PUVA-treated MC and KC supernatants. The concentrations of MC mitogens/growth factors in the PUVA-treated KC supernatants were also determined. In addition, the serum levels of MC mitogens/growth factors in healthy controls, in patients with active vitiligo and in patients with repigmenting vitiligo after PUVA treatment were determined to elucidate the mechanisms of how PUVA induces vitiligo repigmentation in vivo. RESULTS: Our results demonstrated that PUVA treatment did not significantly stimulate the release of MC mitogens/growth factors from KCs. The migration of MCs was also not enhanced after PUVA treatment. The expression of MMP-2 activity in supernatants derived from PUVA-treated MCs was significantly increased as compared with the control group. However, neither MMP-2 nor MMP-9 activity in KC supernatants was stimulated by PUVA treatment. In contrast to NB-UVB, immediate effects of PUVA on MC proliferation and migration were not observed in this study. Sera from patients with repigmenting vitiligo after PUVA treatment contained higher levels of basic fibroblast growth factor, stem cell factor and hepatocyte growth factor as compared with healthy controls and patients with active vitiligo. CONCLUSIONS: Our results indicate that in addition to immune suppression, PUVA treatment creates a favourable milieu for promoting the growth of MCs in patients with vitiligo instead of directly stimulating the regrowth of MCs. Based on our results, we propose that in the active stage of vitiligo, PUVA treatment is the therapy of choice to slow down the destruction of MCs and to create a favourable environment for MCs to survive. In the stable stage of vitiligo, NB-UVB irradiation should be used to stimulate the proliferation and migration of MCs directly.     

CD30+ large cell transformation of mycosis fungoides after psoralen plus ultraviolet A photochemotherapy

Psoralen plus ultraviolet A (PUVA) photochemotherapy is widely used for the therapy of mycosis fungoides (MF). Clinical progression of MF is often associated with an increase in the size of tumour cells known as transformation. We report two patients with CD30+ large cell transformation that appeared after low-dose PUVA therapy for MF. Clinical data, histopathology, immunohistopathology and T-cell receptor gene rearrangement were studied. Nodules consisted of atypical large cells that expressed CD30. Monoclonal rearrangement of T-cell receptors was observed in one case. Low-dose PUVA therapy may be associated with CD30+ large cell transformation in patients with MF.     

Successful treatment of resistant alopecia areata with a phototoxic dose of ultraviolet A after topical 8-methoxypsoralen application

Background: The efficacy of a phototoxic dose of ultraviolet A (UVA) after topical application of 8‐methoxypsoralen (8‐MOP) in the treatment of alopecia areata (AA) was evaluated previously in only one study. However, the possibility of spontaneous regrowth of hair cannot be excluded as sessions were carried out every 3 months. Objective: To determine the efficacy of a phototoxic dose of UVA after topical application of 8‐MOP in the treatment of AA resistant to other lines of treatment. Subjects/Methods: Thirty‐five patients with AA were treated by topical 8‐MOP application to the lesions followed by UVA irradiation using a phototoxic dose every 3 months for a maximum of four sessions. Severity grading of AA was carried out using the Severity of Alopecia Tool (SALT) score before and after treatment. Results: Fifty‐seven percent of patients showed a positive treatment response (40% showed complete and 17% showed partial response) with significant improvement of SALT score. The mean cumulative UVA dose was 22±8.3 J/cm². Mild reversible side effects were observed in 63% of patients after the first session. Conclusion: Phototoxic psoralen and ultraviolet A therapy after topical application of 0.1% 8‐MOP is an effective treatment option for resistant AA, with low total cumulative UVA dose, few treatment sessions, and minimal reversible side effects.     

Case of localized scleroderma successfully treated with bath psoralen and ultraviolet A therapy

The patient was a 12-year-old girl with linear scleroderma distributed on the right abdomen, dorsal aspect of the right thigh, lower leg and foot. The initial regimen of oral prednisolone and methotrexate, or i.v. methylprednisolone failed in the treatment of the scleroderma. Then bath psoralen and ultraviolet A therapy (bath-PUVA) therapy of 0.2 J–4.0 J/cm² daily to total doses 62.8 J/cm² combined with oral prednisolone was started. After bath-PUVA therapy, regression of the skin sclerosis was observed, the possible mobile range of the right ankle was increased and histological examination confirmed improvement of the sclerosis. The successful results of bath-PUVA therapy in this case suggest its utility for localized scleroderma.     

The optimal time to determine the minimal phototoxic dose in skin photosensitized by topical 8 methoxypsoralen

BACKGROUND: We recently investigated the characteristics of psoralen plus ultraviolet (UV) A erythema in skin photosensitized by topical 8-methoxypsoralen (8-MOP) in three independent studies. OBJECTIVES: In order to determine the optimal time to read the minimal phototoxic dose (MPD) after treatment with topical 8-MOP and irradiation with UVA, we assessed the overall data. METHODS: One forearm of each subject was immersed in 8-MOP solution for 15 min and test sites on the flexor surface of the forearm were immediately exposed to a UVA dose series. Erythema was assessed visually and objectively using a reflectance instrument at 24-h intervals for 7 days. RESULTS: Results were obtained from 44 subjects (predominantly Fitzpatrick skin phototype II). A broad erythemal plateau was evident beyond 72 h and the visual MPD was significantly lower at 96, 120 and 144 h than at 72 h (P < 0.01). Only 30% of subjects were at peak erythema at the conventional MPD assessment time of 72 h. The median time to reach maximal erythema was 96 h (range 48-144). Objectively, 85% of subjects were at peak erythema at or beyond 96 h. CONCLUSIONS: We recommend that (i) the optimal time to read the topical 8-MOP MPD is 4 days after UVA exposure as readings beyond this time may be difficult to interpret because of the development of pigmentation, and (ii) 40% of the topical 8-MOP MPD should be considered for the first treatment.     

A comparison of psoralen plus ultraviolet A (PUVA) monotherapy,tacalcitol plus PUVA and tazarotene plus PUVA in patients with chronic plaque-type psoriasis

BACKGROUND: Numerous studies have shown that the additional administration of topical or systemic antipsoriatic agents might serve as an effective means to increase the efficacy of photochemotherapy [psoralen plus ultraviolet (UV) A (PUVA)] for psoriasis. OBJECTIVES: To compare the therapeutic response to tacalcitol plus PUVA, tazarotene plus PUVA and PUVA monotherapy in patients with chronic plaque-type psoriasis. In addition, we also assessed the duration of remission induced by each regimen and the tolerability of the two combination treatments. METHODS: Thirty-one patients with chronic plaque-type psoriasis were included in this observer-blinded, intrapatient comparison trial. PUVA treatment was given four times weekly. Additionally, tacalcitol ointment and 0.1% tazarotene gel were applied separately on two target areas once daily in the evening. At the onset of therapy and every 2 weeks thereafter the response to treatment was determined by the Psoriasis Severity Index score, which assesses the degree of erythema, infiltration and scaling of the psoriatic lesions. After complete or near complete clearing patients were followed-up until relapse. RESULTS: Twenty-four patients completed the study. The treatment requirements to induce complete or near complete clearing were significantly lower for both combination treatments than for PUVA monotherapy (P < 0.01). The median cumulative UVA dose and number of exposures were 30.6 J cm-2 (95% confidence interval, CI 22.5-71.2) and 14 (95% CI 11-16) for tacalcitol plus PUVA, 32.3 J cm-2 (95% CI 22.5-73.8) and 14 (95% CI 11-19) for tazarotene plus PUVA, and 37.0 J cm-2 (95% CI 29.5-83.9) and 16 (95% CI 14-22) for PUVA monotherapy. No difference between the three regimens was observed with regard to duration of remission. Adverse reactions occurred more often with 0.1% tazarotene than with tacalcitol but were in general mild and completely reversible upon using a lower concentration of 0.05% tazarotene. CONCLUSIONS: Tacalcitol ointment and tazarotene gel are both comparably effective in improving the therapeutic result of PUVA therapy in patients with chronic plaque-type psoriasis. Besides accelerating the treatment response, both agents, by virtue of their UVA dose-sparing effect, might also help to reduce possible long-term hazards of PUVA treatment.     

Variation in calibration of hand-held ultraviolet (UV) meters for psoralen plus UVA and narrow-band UVB phototherapy

BACKGROUND: Phototherapy units should regularly use hand-held ultraviolet (UV) meters to assess the output of treatment lamps, and these meters should be accurately calibrated. Several medical physics departments in the U.K. can calibrate UV meters traceable to national standards, but there is concern that there may be disagreement among departments. In particular, there may be difficulty in calibration for narrow-band UVB phototherapy lamps (TL-01). OBJECTIVES: To ascertain the level of agreement in UV meter calibration at expert centres in the U.K., and to survey methodology at these centres, consider sources of errors and to make recommendations on calibration methods. METHODS: The same UV meter with two detectors (for UVA and UVB) was calibrated by seven medical physics departments. A questionnaire on methods was also distributed and measured spectral outputs from each centre were examined. RESULTS: The calibration factors for the meter varied by +/- 18% for the UVA detector and by +/- 60% for the UVB detector (2 standard deviations). Six centres performed calibration using a spectroradiometer and one centre used a reference meter method. The spectra of lamps used for calibration were similar. For the spectroradiometric methods there were some differences in methodology and instrumentation that may account for the differences in calibration factors. CONCLUSIONS: UV meter calibration in the U.K. shows unacceptable variability, particularly for TL-01 lamps. An accuracy of around of +/- 10% would be clinically acceptable and should be technically achievable.     

Determination of the minimal phototoxic dose and colorimetry in psoralen plus ultraviolet A radiation therapy

BACKGROUND: The use of an adequate initial dose of ultraviolet A (UVA) radiation for photochemotherapy is important to prevent burns secondary to overdosage, meanwhile avoiding a reduced clinical improvement and long-term risks secondary to underdosage. The ideal initial dose of UVA can be achieved based on the phototype and the minimal phototoxic dose (MPD). The objective measurement of constitutive skin color (colorimetry) is another method commonly used to quantify the erythematous skin reaction to ultraviolet radiation exposure. The aim of this study was to determine variations in MPD and constitutional skin color (coordinate L(*)) within different phototypes in order to establish the best initial dose of UVA radiation for photochemotherapy patients. METHODS: Thirty-six patients with dermatological conditions and 13 healthy volunteers were divided into five groups according to phototype. Constitutional skin color of the infra-axillary area was assessed by colorimetry. The infra-axillary area was subsequently divided into twelve 1.5 cm(2) regions to determine the MPD; readings were performed 72 h after oral administration of 8-methoxypsoralen (MOP) followed by exposure of the demarcated regions to increasing doses of UVA. Results: The majority of the participants were women (73.5%) and their mean age was 38.8 years. The MPD ranged from 4 to 12 J/cm(2) in phototypes II and III; from 10 to 18 J/cm(2) in type IV; from 12 to 24 J/cm(2) in type V and from 18 to 32 J/cm(2) in type VI. The analysis of colorimetric values (L(*) coordinate) and MPD values allowed the definition of three distinctive groups of individuals composed by phototypes II and III (group 1), types IV and V (group 2), and phototype VI (group 3). CONCLUSIONS: MPD and L(*) coordinate showed variation within the same phototype and superposition between adjacent phototypes. The values of the L(*) coordinate and the MPD lead to the definition of three distinct sensitivity groups: phototypes II and III, IV and V and type VI. Also, the MPD values bear a strong correlation to coordinate L(*) values. Mean MPD values described for each of the three major sensitivity groups were higher than the values commonly used in clinical settings for the different phototypes. Therefore, phototype alone is not a good parameter to define the initial UVA dose. MPD and colorimetry could be used in pre-treatment evaluation of patients who are to be submitted to photochemotherapy, in a non-invasive and more accurate way when compared with the classical phenotype clinical criteria.     

Lichen planus of the lower limbs: successful treatment with psoralen cream plus ultraviolet A photochemotherapy

Lichen planus (LP) classifies into different subtypes depending on morphology and localization. Localized LP of the lower limb (LPLL) manifests a great challenge due to persistent itching, therapeutic resistance and the risk to develop into SCC. We report two cases with LPLL refractory to standard topical therapy, which were successfully treated with psoralen cream plus UVA photochemotherapy (cream‐PUVA). We propose cream‐PUVA as an alternative therapeutic option effective for localized LP of the lower limbs.     

The effect of psoralen plus ultraviolet A in vitro in HUT-78 enhances by 5-aminolevulinic acid

BACKGROUND: Sezary syndrome and mycosis fungoides are forms of cutaneous T-cell lymphoma, and in the early stage of these diseases psoralen plus ultraviolet A (PUVA) is one of the treatments of choice. Photodynamic therapy using 5-aminolevulinic acid (ALA-PDT) is an effective, non-invasive, and safe treatment for most superficial skin cancers. In order to obtain greater efficacy of PUVA, we investigated the synergistic anti-tumor effects of ALA-PDT and PUVA using 8-methoxypsoralen (8-MOP) and a UVA lamp. METHODS: The in vitro effects of PUVA and ALA-PDT and their combination in HUT-78 cell line from human SS were determined by MTT assay. RESULTS: In our results, cell proliferation compared with controls was inhibited to 53.2% with UVA alone, 52.3% with 1 microM 8-MOP, 43.8% with 100 microM ALA, and 19.2% with combined 8-MOP and ALA. CONCLUSION: Combined use of ALA and PUVA using 8-MOP and UVA lamps, which are widespread in Japan, had a strong anti-tumor effect in vitro. Combined treatment with ALA-PDT and PUVA using a UVA lamp appears to have a strong treatment effect.     

Comparison of the efficacy of local narrowband ultraviolet B (NB-UVB) phototherapy versus psoralen plus ultraviolet A (PUVA) paint for palmoplantar psoriasis

Palmoplantar psoriasis is an idiopathic disabling condition, often resistant to conventional therapies. The purpose of this study was to evaluate the efficacy and safety of local narrowband ultraviolet B (NB-UVB) phototherapy and to compare it with local psoralen plus ultraviolet A (PUVA) paint in patients with palmoplantar psoriasis unresponsive to conventional therapies other than phototherapy. A cohort of 25 patients with palmoplantar psoriasis were included in this study, which was based on a left-to-right comparison pattern. The treatments were administered with local narrowband UVB irradiation on one side and local PUVA on the other side three times a week over 9 weeks. Clinical assessments were performed at baseline and every 3 weeks during the 9-week treatment. There was a statistically significant decrease in the mean clinical scores at the third, sixth and ninth week with both treatments. The difference in clinical response between the two treatment modalities was statistically significant at the end of the treatment period, with the percentage reduction in severity index scores with the PUVA-paint-treated side being 85.45% compared with 61.08% for the NB-UVB treated side (t = 5.379, P = 0.0001, Student's t-test for unpaired samples). Our results show that, although some clinical improvement was achieved with local NB-UVB phototherapy, the results were better with local PUVA, and such a treatment option may be reserved for patients with palmoplantar psoriasis who experience phototoxic reaction to psoralens.     

Ultrastructural changes induced in cutaneous collagen by ultraviolet-A1 and psoralen plus ultraviolet A therapy in systemic sclerosis

In the present study, we examined the ultrastructural alterations in collagen fibrils clinically softened by ultraviolet-A1 (UVA1, 340-400 nm) therapy and psoralen plus long-wave ultraviolet (PUVA) therapy and compared collagen fibril diameters in four patients with systemic sclerosis (SSc). In skin sclerosis, the dermis is compacted from the epidermal layer to the sweat glands, and the collagen bundles are thicker with decreased space between them. We obtained skin specimens before and after UVA1 or PUVA therapy, and compared cutaneous alterations in one diffuse-type patient and one limited-type patient following UVA1 therapy, and in two diffuse-type patients following PUVA treatment. Ultramicroscopic analysis revealed that UVA1 treatment decreased the diameter of the broad collagen fibrils, mainly in the upper reticular layer. PUVA induced similar alterations in the collagen fibrils, extending to the upper and middle reticular layers. PUVA therapy induced alterations in collagen fibril diameter in deeper layers than did UVA1 therapy, which might be related to the direct action of UV light and the depth of the light penetration. In three of four patients, collagen fibril diameter decreased, collagen fibril thickness equalized, and new, thin fibrils developed among the collagen fibrils, suggesting that collagen degradation and synthesis underlie the alterations induced by UVA1 and PUVA phototherapies.     

Modulation of ultraviolet (UV) transmission by emollients: relevance to narrowband UVB phototherapy and psoralen plus UVA photochemotherapy

BACKGROUND: Patients with psoriasis undergoing or about to undergo ultraviolet (UV) phototherapy and photochemotherapy often have thick scale on their plaques which can prevent the penetration of UV radiation. Emollients are used to moisturize the skin and to prevent or reduce some of the milder side-effects ('dryness', itching) sometimes experienced during UV therapy. However, emollients can alter the UV transmission of skin and thus may alter the clinical effects of phototherapy and photochemotherapy. OBJECTIVES: We tested 30 of the topical emollients in the British National Formulary (BNF) using a standard in vitro technique used to test sunscreens. We also surveyed U.K. phototherapy units to establish routine practice for emollient use in phototherapy and photochemotherapy. METHODS: We used a standard in vitro technique to measure the monochromatic protection factors (MPFs) of 30 non-bath emollients from the BNF. An application rate of 2 mg cm-2 was used. For the assessment of effects during narrowband UVB (TL-01) phototherapy, the mean of the protection factors at 310 and 315 nm was calculated; for psoralen plus UVA photochemotherapy the mean UVA protection factor was used. A questionnaire survey was used to assess routine practice concerning emollient use prior to phototherapies in phototherapy units throughout the U.K. RESULTS: In the UVA range, 17 of the 30 emollients gave protection factors of 1.2 or above. In the UVB range, 23 of 30 had an MPF of 1.2 or above. Yellow soft paraffin had the highest protection factor in the UVB range. Of 78 centres surveyed, 57 returned completed questionnaires (73%). Seventeen of 57 (30%) centres routinely used emollients immediately prior to administering phototherapy treatments. The remaining 40 of 57 (70%) did not. Forty-five (79%) responding centres recommended the use of emollients after phototherapy. CONCLUSIONS: This study has revealed considerable variability in the practice of emollient use before phototherapy treatments. Although the majority of centres included in this study did not routinely use emollients, almost one third did. Our in vitro measurement of 30 emollients revealed marked variation in UV transmission, with many emollients blocking sufficient UV to affect the response to therapy.