Topical photodynamic therapy in the treatment of hidradenitis suppurativa.

Topical photodynamic therapy (PDT) is well established for the treatment of malignant and pre-malignant skin lesions and now it is increasingly used to treat benign dermatological conditions. The studies reporting the use of PDT in hidradenitis suppurativa are reviewed. Though small in number, there is considerable variation in the application of topical photosensitisers, light sources used and treatment regimes. In addition there is often limited information about patient selection in terms of disease severity and measuring precise patient outcome. These issues need to be addressed in future studies in order to accurately determine the role of PDT in this disease.

Microbiological effect of photodynamic therapy (PDT) in healthy volunteers: a comparative study using methyl aminolaevulinate and hexyl aminolaevulinate cream.

BACKGROUND: Acne vulgaris is a common skin problem that affects up to 90% of adolescents. Colonization of the duct with Propionibacterium species is one of the factors implicated in the development of acne. Owing to the increasing incidence of antibiotic resistance, there has been an greater interest in the development of new methods to treat acne. Early studies have shown that photodynamic therapy (PDT) with aminolaevulinic acid (ALA) can lead to prolonged improvement in acne. Newer derivatives of ALA such as methyl aminolaevulinate hydrochloride (MAL) and hexyl aminolaevulinate hydrochloride (HAL) have been developed for use in PDT, with the potential benefits of higher lipophilicity and penetration potential. OBJECTIVES: To determine the microbiological effect and tolerability of a single application of HAL-PDT and to compare it with MAL-PDT in healthy volunteers. METHODS: This was a randomised double-blind study to examine the microbiological effects and safety of a single application of MAL-PDT and HAL-PDT on normal skin in 18 healthy volunteers. Bacterial skin samples for Propionibacterium spp. and Micrococceae were obtained at baseline and 2, 4, 7 and 14 days. RESULTS: Following PDT with MAL and HAL, a statistically significant transient reduction in mean density of Propionibacterium spp. 2 days after treatment using each agent (P < 0.05 for both) was found. There were no significant changes in mean number of Micrococceae for the duration of the study period. Treatment with HAL-PDT and MAL-PDT was well tolerated. Overall, HAL-PDT was associated with fewer side-effects compared with MAL-PDT (P < 0.01) over the 14 day study period. CONCLUSION: HAL-PDT and MAL-PDT transiently reduce density of Propionibacterium spp. density to a similar degree in normal healthy individuals. The transient reduction in Propionibacterium spp. suggests that the prolonged antiacne effect of PDT relies on factors independent of bacterial density. HAL-PDT appears to be better tolerated than MAL-PDT.

Topical photodynamic therapy for non-cancerous skin conditions.

Topical photodynamic therapy (PDT) is a non-invasive therapeutic modality which is developing increasing use in dermatology. It is a well established treatment for pre-malignant and malignant skin tumours and over recent years there has also been encouraging evidence for its use in treating benign cutaneous disorders. We review the literature and clinical trials utilising topical PDT for non-cancerous skin conditions. Recalcitrant warts, acne vulgaris and psoriasis have so far been studied in most detail. At present, photosensitisers, light sources and treatment parameters of PDT vary in different clinical trials even for the same conditions. Optimum parameters for PDT need to be established and comparison randomised studies are required to clarify whether PDT for benign dermatoses is significantly superior to existing therapeutic modalities.

Efficacy of oral isotretinoin in the control of skin and nasal colonization by antibiotic-resistant propionibacteria in patients with acne.

BACKGROUND: Skin colonization by antibiotic-resistant propionibacteria is commonplace among acne patients globally. Increasing attention is now being paid to how resistance rates might be reduced to preserve the future efficacy of antibiotics, especially erythromycin and clindamycin in acne therapy. OBJECTIVE: To assess the efficacy of oral isotretinoin in the control of antibiotic-resistant propionibacteria. METHODS: Acne patients (72 in the U.K., 62 in the U.S.A.) colonized with high numbers of antibiotic-resistant propionibacteria were sampled before, during and 12 weeks after oral isotretinoin therapy. Propionibacterial samples were collected from five acne-prone skin surface sites using a detergent scrub method and from the anterior nares using moistened swabs. Total and antibiotic-resistant propionibacteria were enumerated by viable counting on media with and without selective antibiotics. RESULTS: After 16 weeks of oral isotretinoin therapy, mean population densities of viable propionibacteria and variants resistant to erythromycin, clindamycin or tetracycline had fallen by more than 90% at all skin sites and in the nares. The sole exception was a smaller reduction in tetracycline-resistant strains on the lower back. In general, greater reductions were observed on skin than in the nares. By the end of the treatment period only three patients (all in Philadelphia) yielded no antibiotic-resistant strains from any site. Post-treatment, propionibacterial counts remained well below pretreatment levels but had begun to recover on the face and in the nares. The recovering propionibacterial population included both susceptible and resistant strains. Changes during and post-treatment at the two centres were similar but not identical. CONCLUSIONS: Oral isotretinoin effectively reduced skin and nasal colonization by antibiotic-resistant propionibacteria. However, viable populations of resistant isolates persisted post-treatment at multiple sites. Novel methods are required to eradicate antibiotic-resistant propionibacteria completely, especially from the nasal reservoir.

Compliance of renal transplant recipients with advice about sun protection measures: completing the audit cycle.

Renal transplant recipients are at increased risk for development of nonmelanoma skin carcinoma, owing to a number of causes, including ultraviolet exposure. It has been shown that, despite education, there is poor compliance by these patients with the advice given for protecting their skin from the sun. This repeat study was conducted to determine whether there had been an improvement in compliance over the last 6 years. Two hundred twenty-seven patients were invited to complete the questionnaire used in the previous study. This questionnaire was designed to establish whether patients understood the need for extra care, whether they recalled any education about protective measures, and what actual measures were taken. There was a significant increase in the proportion of patients taking appropriate precautions. Hence there has been a significant improvement in the compliance of renal transplant recipients in Yorkshire with skin protection measures since this was originally audited in 1998.

Topical aminolaevulinic acid-photodynamic therapy for the treatment of acne vulgaris: a study of clinical efficacy and mechanism of action.

BACKGROUND: Acne affects 83-95% of 16-year-olds of both sexes, and many seek help from a clinician. Emerging problems with conventional acne treatments, specifically antibiotic resistance of Propionibacterium acnes and fears over the safety and tolerance of oral isotretinoin, create a demand for novel treatment modalities in acne. OBJECTIVES: To study the efficacy of aminolaevulinic acid-photodynamic therapy (ALA-PDT) in the treatment of acne and to identify the mode of action, looking specifically at the effects on surface numbers of P. acnes and on sebum excretion. METHODS: Ten patients (nine men and one woman, age range 16-40 years) with mild to moderate acne on their backs were recruited. Each patient's back was marked with four 30-cm2 areas of equal acne severity. Each site was then randomly allocated to either ALA-PDT treatment, light alone, ALA alone or an untreated control site. At baseline, numbers of inflammatory and noninflammatory acne lesions were counted, sebum excretion measured by Sebutapes (CuDerm, Dallas, TX, U.S.A.) and surface P. acnes swabs performed. ALA cream (20% in Unguentum Merck) was applied under occlusion to the ALA-PDT and ALA alone sites for 3 h. Red light from a diode laser was then delivered to the ALA-PDT and light alone sites (635 nm, 25 mW cm(-2), 15 J cm(-2)). Each patient was treated weekly for 3 weeks. At each visit acne lesion counts were performed and 3 weeks following the last treatment sebum excretion rates and P. acnes swabs were repeated. RESULTS: There was a statistically significant reduction in inflammatory acne lesion counts from baseline after the second treatment at the ALA-PDT site but not at any of the other sites. No statistically significant reduction in P. acnes numbers or sebum excretion was demonstrated at any sites including the ALA-PDT site. CONCLUSIONS: ALA-PDT is capable of clinically improving acne. An alternative mode of action for ALA-PDT other than direct damage to sebaceous glands or photodynamic killing of P. acnes is suggested from the results of this study.

Disseminated cutaneous infection with Mycobacterium chelonae in a patient with steroid-dependent rheumatoid arthritis.

Mycobacterium chelonae is a rapidly growing atypical mycobacterium that is a normal commensal of water and soil. We report a case of a 61-year-old man with seronegative rheumatoid arthritis and fibrosing alveolitis on long-term prednisolone who presented with a number of tender, red, subcutaneous nodules on his upper arms and a pustule on his left cheek. Histopathologic examination revealed dense neutrophilic collections within the deep dermis and subcutaneous fat with abscess formation. Long filamentous organisms were seen within these collections and were subsequently identified by special stains and PCR as Mycobacterium chelonae. Treatment was not possible as the patient developed bacteria bronchopneumonia before identification of the organism and he subsequently died. Post-mortem revealed no extra-cutaneous evidence of mycobacterium infection.

Comedogenesis: some aetiological, clinical and therapeutic strategies.

Hypercornification is an early feature of acne and usually precedes inflammation. It is associated with ductal hyperproliferation, and there are many controlling factors such as androgens, retinoids, sebum composition and cytokines. Cycling of normal follicles and of comedones may explain the natural resolution of comedones and, in the longer term, resolution of the disease itself. There is a need to tailor treatment according to comedonal type. Suboptimal therapy can often result from inappropriate assessments of comedones, especially microcomedones, sandpaper comedones, submarine comedones and macrocomedones. Macrocomedones can produce devastating acne flares, particularly if patients are inappropriately prescribed oral isotretinoin. Gentle cautery under topical local anaesthesia is a useful therapy in the treatment of such lesions. The newer retinoids and new formulations of all-trans-retinoic acid show a better benefit/risk ratio.

Allergic otitis externa.

Chronic otitis externa is a common condition, which is usually successfully treated by topical medications and aural toilet. In cases that persist despite conventional treatment, a diagnosis of allergic otitis externa should be considered. Sensitization to otic medications (secondary contact otitis) is not uncommon. Topical aminoglycosides are the most common sensitizers although many components of topical preparations can cause sensitization. Patients who may have developed allergic otitis externa should undergo patch testing. Otolaryngologists should consider using topical antibiotics with a low allergenic potential and avoiding neomycin when treating patients with otitis externa. Primary contact otitis may occur to metals used in earrings and also to hearing aid moulds. Treatment of both primary and secondary contact otitis consists of identifying the allergen, avoiding further contact and use of simple preparations avoiding common sensitizers.

A double-blind investigation of the potential systemic absorption of isotretinoin, when combined with chemical sunscreens, following topical application to patients with widespread acne of the face and trunk.

This study assessed the systemic absorption of isotretinoin and its metabolites, during a 4-week application of a cream containing 0.1% isotretinoin and chemical sunscreens, compared with a 4% benzoyl peroxide cream, in patients with acne on the face and trunk. Blood was drawn at weeks 0, 1, 2, 3 and 4 and at 96 h post-treatment. Plasma levels of isotretinoin (13-cis-retinoic acid) and tretinoin (all-trans-retinoic acid) were quantified by liquid chromatography with tandem mass spectrometry and the presence of their combined 4-oxo metabolites were monitored from the peak area ratios observed. The isotretinoin group showed no statistically or clinically significant increases in plasma retinoid levels and mean levels did not exceed +/-2 SD of the mean pre-treatment values, indicating that endogenous levels were not being exceeded. No significant differences were detected between the isotretinoin group and the 4% benzoyl peroxide group. These findings indicated that retinoid absorption from a cream containing 0.1% isotretinoin and chemical sunscreens was clinically insignificant, when applied to patients with widespread acne.

Comedogenesis: some new aetiological, clinical and therapeutic strategies.

Hypercornification is an early feature of acne and precedes inflammation. It is associated with ductal hyperproliferation and there are many controlling factors such as androgens, retinoids and cytokines. Cycling of normal follicles and of comedones may explain the natural resolution of comedones and, in the longer term, resolution of the disease itself. There is a need to tailor treatment according to comedonal type. Suboptimal therapy can often result from inappropriate assessments of comedones, especially microcomedones, missed comedones, sandpaper comedones, submarine comedones and macrocomedones. Macrocomedones can produce devastating acne flares, particularly if patients are inappropriately prescribed oral isotretinoin. Gentle cautery under topical local anaesthesia is a useful therapy in the treatment of such lesions. The newer retinoids and new formulations of all-trans-retinoic acid show a better benefit/risk ratio. Evidence-based studies are required to allow adequate comparisons.

Scleredema associated with paraproteinaemia treated by extracorporeal photopheresis.

Scleredema is a rare disease characterized by extensive cutaneous woody, non-pitting induration that spreads throughout the body. We describe a patient with scleredema associated with paraproteinaemia who was successfully treated by extracorporeal photopheresis.