Validation of a semiautomated method of minimal erythema dose testing for narrowband ultraviolet B phototherapy

BACKGROUND

The most widely used method for establishing the minimal erythema dose (MED) before narrowband ultraviolet (UV) B phototherapy is time-consuming, inconvenient and may yield inconsistent results.

OBJECTIVES

To assess the equivalence of MED assessment using a filtered xenon arc lamp UV source, a semiautomated MED tester, and a UV-opaque template method of MED determination with a panel of TL-01 311-nm UVB fluorescent tubes. Secondly, to gauge the current usage of MED testing, and the method used, in a large sample of U.K. phototherapy units. Thirdly, to assess variation in UV output of the semiautomated skin tester immediately after switching on to identify optimum warm-up time. Finally, to assess reproducibility of MED testing by assessing within-patient variability and interobserver variability of MED test results.

METHODS

Sixty-five patients about to undergo UVB phototherapy had their MED determined using three different methods. Within each patient we compared the values of MED determined by a semiautomated Durham MED tester, a panel of narrowband UVB lamps with a UV-opaque template constructed by a phototherapist, and a 310-nm filtered xenon arc lamp with a liquid light guide. MED test results were assessed by clinical evaluation using a 6500 K colour temperature examination lamp. The output of the semiautomated MED tester was measured by spectroradiometer over a period of 20 min in order to identify the time to steady output. Reproducibility of MED testing with the semiautomated MED tester was carried out in 25 normal volunteers. All MEDs were assessed by at least two independent observers. A postal questionnaire was sent to 78 U.K. phototherapy units to assess routine practice concerning MED testing prior to narrowband UVB phototherapy.

RESULTS

The semiautomated MED tester showed consistency with the panel method (r = 0.92, panel MED = -0.57 + 1.14 x Durham MED). The semiautomated MED tester produced a slightly lower MED result than the panel MED. Reproducibility tests showed high interobserver agreement (kappa value = 0.79), and high consistency for successive day testing (kappa value = 0.79). Questionnaires were returned from 67 of 78 phototherapy units (85%) and revealed that 19 units (28%) were routinely using MED testing prior to UVB therapy.

CONCLUSIONS

This study has shown the Durham MED tester to be a convenient, valid and reproducible method for determining patient MED values prior to narrowband UVB phototherapy when used under carefully controlled lighting, by experienced observers.

Erythropoietic protoporphyria in the U.K.: clinical features and effect on quality of life

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare inherited photodermatosis that causes lifelong painful photosensitivity. Neither its full clinical spectrum nor its impact on quality of life (QoL) has been investigated in a large cohort of patients.

OBJECTIVES

To document the clinical features of EPP and its impact on QoL in a high proportion of all patients with EPP resident in the U.K.

METHODS

Patients with EPP were identified from U.K. clinical databases and assessed by the same clinical investigator over a 7-month period using a standardized proforma and validated adult (Dermatology Life Quality Index, DLQI) and children's (Children's Dermatology Life Quality Index, CDLQI) QoL questionnaires.

RESULTS

Three hundred and eighty-nine living patients with EPP were identified, of whom 223 [114 females, 109 males; median age 34 years (range: 5-87), from 193 families] were investigated. Total erythrocyte porphyrin (TEP) was higher in males (median: 25.3 micromol L1) than females (median: 19.3 micromol L1). The median ages at onset and diagnosis were 1 and 12 years, respectively. Median times for onset of symptoms after sun exposure, onset of signs (oedema, erythema) and resolution of symptoms were 20 min, 6 h and 3 days, respectively. Most patients reported absence of protection by glass (92%), priming (85%), exacerbation by wind (68%), no family history of photosensitivity (56%), no symptoms during winter (56%) and had chronic skin lesions (79%). Symptoms changed little with age but improved during pregnancy in 47% of gravid women. Most patients used protective clothing and a sunscreen; 28% were taking beta-carotene and a further 56% had taken it; 29% were not under regular medical care. Two patients (1%) had liver failure and 8% reported gallstone disease. QoL was markedly impaired, with scores similar to those in severe dermatological disease (mean DLQI score 14.0, n = 176; mean CDLQI score 12.8, n = 44), indicating a large effect on patients' lives. DLQI scores correlated weakly with TEP (rs = 0.228; P = 0.002) and time to onset of symptoms (rs = -0.233; P = 0.002) but not with age at onset.

CONCLUSIONS

EPP is a persistent, severely painful, socially disabling disease with a marked impact on QoL. Its diagnosis is often overlooked. None of TEP, age at onset nor time to onset of symptoms is a useful predictor of impaired QoL in individual patients.

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.

Photosensitive Smith-Lemli-Opitz syndrome is not caused by a single gene mutation: analysis of the gene encoding 7-dehydrocholesterol reductase in five U.K. families

BACKGROUND

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive malformation syndrome characterized by a disorder in cholesterol metabolism. SLOS is caused by mutations in the DHCR7 gene which encodes 7-dehydrocholesterol reductase, an enzyme that catalyses the final step in cholesterol biosynthesis. We have previously established the clinical and photobiological features of the photosensitivity that is frequently a feature of SLOS.

OBJECTIVES

In this study, we have performed mutational analysis of the DHCR7 gene in individuals from five families with SLOS. In each family, one member was affected by severe photosensitivity as a manifestation of SLOS.

METHODS

Fifteen samples (including family controls) were screened using polymerase chain reaction amplification and direct automated sequencing.

RESULTS

Six different DHCR7 mutations were identified of which five were single point mutations that caused missense amino acid substitutions (P51H, T93M, L99P, E448K and R450L). The other was a splice site mutation (G-->C in splice acceptor site) affecting the intron 8-exon 9 splice junction (IVS8-1 G-->C). This splice site mutation and four of the five missense mutations have been previously published as causal in SLOS but the P51H is a novel mutation which has not previously been reported.

CONCLUSIONS

This is the first study in which DHCR7 gene mutational analysis has been performed on SLOS subjects with severe photosensitivity and indicates that no single mutation is responsible for the photosensitivity which characterizes this disorder.

Guidelines for prescribing azathioprine in dermatology

Azathioprine has been available as an immunosuppressive agent for over 40 years, and current routine usage in dermatology is not restricted to licensed indications. Advances in understanding the metabolic fate of azathioprine have led to significant changes in prescribing practice and toxicity monitoring by U.K. dermatologists. The current state of knowledge concerning the use of azathioprine in dermatology is summarized, with identification of strength of evidence. Clinical indications and contraindications for azathioprine usage in dermatology are identified. Evidence-based recommendations are made for routine safety monitoring of patients treated with azathioprine, including pretreatment assessment of red blood cell thiopurine methyltransferase activity.

Rosacea fulminans in pregnancy

Rosacea fulminans is a rare condition with a female preponderance and unknown aetiology, characterized by the abrupt onset of papules, pustules and erythema affecting the face. Corticosteroids and isotretinoin are regarded as the two main therapeutic agents. We report a case associated with pregnancy, and discuss the therapeutic implications. This is the first published report of rosacea fulminans in pregnancy complicated by stillbirth.

Phototherapy and PUVA photochemotherapy in children

The use of phototherapy and photochemotherapy in children has been limited due to concerns over their long-term carcinogenic potential. Furthermore, the method of administration is disconcerting to some children, particularly as phototherapy treatment units are seldom rendered 'child-friendly'. Despite these reservations, ultra-violet therapies can be useful treatment options for children with selected dermatological conditions provided they are used under carefully controlled conditions.

Erythrocyte thiopurine methyl transferase assessment prior to azathioprine use in the UK

BACKGROUND

Individuals with low activity of a key metabolic enzyme, thiopurine methyl transferase (TPMT), are more susceptible to azathioprine-induced myelosuppression.

AIM

To determine the pattern of use of TPMT activity estimation, with respect to azathioprine use, by medical practitioners in the UK.

DESIGN

Retrospective analysis of assay use.

METHODS

We analysed all test results (n=3291), and patient and practitioner details, from inception of TPMT assay in 1990 to the end of December 2000, held at the Purine Research Laboratory, Guy's Hospital, London. Patient details were anonymized. Repeat analyses and requests from outside the UK were excluded.

RESULTS

The male:female ratio was approximately equal and the mean age was 46.6 (range 0.5-97) years. Thirteen different medical specialities requested assays; Dermatology and Gastroenterology were the most frequent users, together accounting for 86% of requests. The numbers of centres requesting the assay varied widely both within and between different specialities. Some 80% of individuals had normal TPMT activity, 9% enzymic activity above normal, and 10% low activity. Fifteen had no detectable enzymic activity: 0.45% (1:220) of the study population.

DISCUSSION

This incidence of undetectable enzyme activity is significantly higher than the previously reported level of 1:300 derived from smaller studies, and makes the economics of screening more attractive.

Systemic photoprotection with alpha-tocopherol (vitamin E) and beta-carotene

Cutaneous photodamage is partly mediated via oxidative pathways and there is evidence to suggest that antioxidants within the skin may have a photoprotective effect. Antioxidant activity is provided by a number of naturally occurring substances including alpha-tocopherol (vitamin E) and beta-carotene, whose effects are mediated by their capacity to quench singlet oxygen, scavenge free radicals and prevent the formation of free radicals. Beta-carotene has been used as treatment for various photosensitivity disorders for more than 30 years. The main indication for its use is in the treatment of the photosensitivity associated with erythropoietic protoporphyria. A role for beta-carotene in the prevention of non-melanoma skin cancer has yet to be demonstrated despite clinical research activity in this area. The role for alpha-tocopherol as a photoprotective agent is less clear-cut and it has yet to be established as treatment either for conditions characterized by photosensitivity or as an agent for preventing chronic photodamage or cutaneous malignancy.

Guidelines for dosimetry and calibration in ultraviolet radiation therapy: a report of a British Photodermatology Group workshop

This report examines the dosimetry of ultraviolet (UV) radiation applied to dermatological treatments, and considers the definition of the radiation quantities and their measurement. Guidelines are offered for preferred measurement techniques and standard methods of dosimetry. The recommendations have been graded according to the American Joint Committee on Cancer classification of strength of recommendation and quality of evidence (summarized in Appendix 5).

Psoralen photochemotherapy (PUVA) is only moderately effective in widespread vitiligo: a 10-year retrospective study

A 10-year retrospective analysis of the use of psoralen photochemotherapy (PUVA) in the treatment of vitiligo was undertaken at the St John's Institute of Dermatology, London, UK. Of 97 patients included in this study, eight had complete or almost complete repigmentation, 59 moderate to extensive repigmentation, and 30 showed little or no response. However, 24 of those who had responded to PUVA with extensive repigmentation did not consider their response satisfactory because of persistence of vitiligo at cosmetically sensitive sites, and poorly matching, speckled repigmentation. Fifty-seven patients who initially improved with PUVA therapy subsequently relapsed, in most cases within a year of stopping treatment. Relapses in 22 patients were on the same cutaneous sites as previously affected, while vitiligo at new sites developed in 20 patients and both new and old sites were affected in a further 15 patients. Patients who retained their pigmentation after 2 years appeared to have a better chance of permanent remission. The only statistically significant prognostic indicator of relapse was patient age at the start of treatment, younger patients tending to retain their pigmentation longer than older patients. This study emphasizes the need for careful patient counselling before PUVA therapy as this treatment seldom achieves extensive repigmentation that is cosmetically acceptable, and treatment response is often followed by relapse.

U.K. guidelines for the management of cutaneous melanoma

These guidelines for management of cutaneous melanoma present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation. To reflect the collaborative process for the U.K., they are subject to dual publication in the British Journal of Dermatology and the British Journal of Plastic Surgery.

UK guidelines for the management of cutaneous melanoma

These guidelines for management of cutaneous melanoma present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation. To reflect the collaborative process for the UK, they are subject to dual publication in the British Journal of Dermatology and the British Journal of Plastic Surgery.

Rifampicin-induced lupus erythematosus

Rifampicin has been prescribed throughout the world for over 20 years, yet only four cases of rifampicin-induced lupus erythematosus (LE) have been reported. Rifampicin-induced LE is associated with combination therapy with clarithromycin or ciprofloxacin. These drugs are all metabolized through the cytochrome P450 liver enzyme system and combined usage may lead to higher rifampicin blood levels. Drug-induced LE differs from systemic LE; cutaneous manifestations, although uncommon, are an important clue to the diagnosis. We report a case of rifampicin-induced LE presenting with florid cutaneous features.

Bowen's disease, solar keratoses and superficial basal cell carcinomas treated by photodynamic therapy using a large-field incoherent light source

BACKGROUND

Photodynamic therapy (PDT) has not yet been demonstrated to be superior to conventional treatment in the treatment of superficial skin cancers and premalignant skin conditions. A limitation for PDT is the absence to date of a light source suitable for the treatment of larger lesions or 'field changes' where several lesions are present on one anatomical site.

OBJECTIVES

To investigate the safety and efficacy of a large field light source, the Waldmann PDT 1200, in the treatment of Bowen's disease (BD), superficial basal cell carcinomas (BCCs) and solar keratoses (SKs).

METHODS

After application of 5-aminolaevulinic acid for 4-6 h, each lesion was irradiated with 105 J cm-2 of incoherent red light centred on 640 nm. Eighty-eight patients with 239 lesions were recruited.

RESULTS

Within two treatments, 88% of BD lesions, 95% of BCCs and 99% of SKs showed complete clinical clearance. At 12 months the complete response rates were 69% for BD, 82% for BCC and 72% for SK.

CONCLUSIONS

This study confirms that PDT is a useful treatment and that selected superficial BCCs and SKs respond well to PDT. The PDT 1200 light source proved capable of treating multiple lesions amounting to a 'field change' and also lesions up to 10 cm in diameter within an acceptable treatment time. Thus far, PDT has failed to become established as a routine treatment for small premalignant and malignant skin lesions as it has not proved superior to simple cheaper conventional therapies such as cryotherapy, curettage and cautery, topical chemotherapy with 5-fluorouracil, or surgery. However, PDT has become established as a treatment for selected cases in some centres. This study suggests a role for PDT in the treatment of large premalignancies, superficial BCCs and field change where existing treatments may be problematic.

Cholesterol supplementation objectively reduces photosensitivity in the Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz (SLO) affected children have multiple congenital physical and mental abnormalities; photosensitivity to ultraviolet A (UVA) has recently become a recognized feature. We present a patient with SLO and prominent photosensitivity in whom detailed phototesting has been performed at baseline and following 6 months of cholesterol supplementation. There was significant improvement in the symptoms of photosensitivity, confirmed objectively by phototesting and accompanied by partial correction of the biochemical abnormalities seen in SLO. This case report is the first to show that cholesterol supplementation in SLO can lead to an objective improvement in the associated photosensitivity.

Aquagenic pruritus responding to intermittent photochemotherapy

Aquagenic pruritus is a rare but distinct entity in which intense itching develops after contact with water, in the absence of cutaneous signs or underlying disorders that could explain the symptoms. The aetiology is currently unknown, and treatment difficult, with a poor response to antihistamines. Psoralen-ultra violet A (PUVA) photochemotherapy can be effective, but frequent maintenance therapy may be required to prevent relapse of symptoms. We present a patient with typical aquagenic pruritus who responded well to PUVA, and who has remained well controlled on infrequent maintenance.

Severe digital necrosis in an elderly patient with heterozygous factor V Leiden mutation

We report an 81-year-old female with a heterozygous factor V Leiden mutation who developed purpura fulminans. Digital necrosis, a characteristic clinical feature of purpura fulminans was prominent. Purpura fulminans is more common in children and adult cases are rare. Of eight reported cases of purpura fulminans resulting from a heterozygous factor V Leiden mutation recorded in the literature, only two were in adults: 40 and 42 years of age, respectively. This is the first report of this condition arising in a patient in her eighties.