ANTIBIOTIC PRESCRIBING FOR SKIN CONDITIONS
GPs have not limited their prescribing of antibiotics for skin conditions, despite a fall in the incidence of skin infections, the results of a population-based analysis show. Researchers examined trends in the incidence of skin infections in relation to trends in dispensed prescriptions for flucloxacillin, topical fusidic acid, mupirocin and corticosteroids with fusidic acid. The incidence of skin infections among children (0-14 years) fell between 1999 and 2005, but remained fairly constant among adults (>14 years). Despite this, the researchers found annual increases in dispensed flucloxacillin capsules. There was little change in flucloxacillin syrups and topical antibiotic preparations.
Fleming DM, Elliot AJ, Kendall H. Br J Gen Pract 2007;57:569-73
VAC THERAPY BENEFITS REVIEWED
The efficacy of topical negative pressure, or VAC therapy, for wound healing has been questioned in a review. The authors say that many of the studies investigating the technique are flawed and thus the validity of any observed results is doubtful. They add that there is no compelling evidence of VAC therapy speeding up healing of bed sores or uncomplicated diabetic foot ulcers, or helping skin grafts to 'take'. The reviewers conclude that the clinical effectiveness of the treatment is 'unclear' and there is insufficient evidence to judge its cost-effectiveness compared with other treatments.
Drug Ther Bull 2007;45:57-61
DRESSINGS FOR LEG ULCERS REVIEWED
The type of dressing applied beneath compression bandaging does not appear to affect ulcer healing. The results of a meta-analysis show that hydrocolloid dressings are no more effective than simple low-adherent dressings when used under compression. The reviewers identified 254 studies, of which 42 fulfilled their criteria for inclusion in the review. They conclude that no clear recommendations can be made in terms of which dressing is the most cost-effective and that decisions on which to use should be based on local costs and the preferences of practitioners or patients.
Palfreyman S, Nelson EA, Michaels JA. BMJ 2007;335:244
MELANOMAS AND THE ABCDE RULE
The ABCDE rule for melanoma should be reviewed, according to US researchers. They identified 95 cases of melanoma at one general dermatology practice from 2000 to 2004. Thirteen of these lesions had diameters <4mm at presentation, including five invasive and eight in situ melanomas, and the defining clinical characteristic was intensity of pigment. The researchers say that their findings support other authors who suggest removing the 6mm diameter criterion and provide further evidence that dark colour should be given more emphasis as a diagnostic criterion. They believe 'D for dark', rather than 'diameter', would enhance the value of the rule.
Goldsmith S, Solomon A. J Eur Acad Dermatol Venereol 2007;21:929-34
ENHANCING CYCLOSPORINE ABSORPTION
Cyclosporine is usually administered after meals, but researchers in Japan have found that preprandial administration enhances the drug's absorption. They compared the pharmacokinetics of cyclosporine after pre- and postprandial administration in 12 patients (10 men and two women) aged a mean 47.1 years, with psoriasis vulgaris. Blood samples were collected immediately before and one, two, three and four hours after the treatment. Mean maximum drug concentration was significantly greater after preprandial administration of oral cyclosporine, which the researchers say would potentially allow the daily dose to be reduced compared with postprandial administration of the drug.
Umezawa Y, Mabuchi T, Ozawa A. Int J Dermatol 2007;46:880-2
PUVA AND THE RISK OF CATARACTS
Case reports and animal studies suggest PUVA may increase the risk of lens abnormalities. US researchers have sought to assess this risk. Their prospective 25-year study involved 1,237 patients with psoriasis treated with PUVA, who were also given regular eye examinations. The results show that the age-adjusted incidence of cataract did not increase significantly and increasing exposure to PUVA was not associated with a higher risk of cataract. However, the researchers note that their study cohort involved middle-aged or older patients and therefore the effects of PUVA on younger patients could not be assessed.
Malanos D, Stern RS. J Am Acad Dermatol 2007;57:231-7
OBESITY LINKED TO PSORIASIS
Increased adiposity and weight gain are strong risk factors for psoriasis in women, according to the results of a prospective study. Researchers in the US followed 78,626 women in the Nurses' Health Study II from 1991 to 2005. There were 892 self-reported incident cases of psoriasis. Compared with a BMI of 21-22.9kg/m2, the relative risk of psoriasis was 1.4 for a BMI of 25-29.9kg/m2, 1.48 for a BMI of 30-34.9kg/m2, and 2.69 for a BMI of 35kg/m2 or more. Weight gain from the age of 18, higher waist and hip circumference, and waist-to-hip ratio were all associated with a greater risk of incident psoriasis. Setty AR, Curhan G, Choi HK. Arch Intern Med 2007;167:1670-5
VIRUS MAY INCREASE RISK OF ACTINIC KERATOSES
Betapapillomavirus infection, in combination with key risk factors, increases the risk of actinic keratoses. A study of 291 adults found the infection was associated with having more than 10 actinic keratoses. People aged more than 60 with evidence of the infection had a 13-fold increased risk, while those with fair skin had a sixfold increased risk compared with those who had no evidence of infection and no risk factor.
McBride P, Neale R, Pandeya N, Green A. Arch Dermatol 2007;143:862-8
COFFEE PLUS EXERCISE CAN COMBAT SKIN CANCER
Coffee and exercise can act synergistically to combat skin cancer, according to a US study. Researchers randomised four groups of hairless mice to receive caffeinated water (one to two cups per day human equivalent), an exercise wheel, both interventions, or neither (controls). All were exposed to UVB radiation. Some degree of apoptosis in DNA-damaged cells occurred in all groups, but the caffeine drinkers showed a 92 per cent increase in UVB-induced apoptosis compared with controls, while exercisers showed a 120 per cent increase and mice drinking caffeine and exercising showed almost a 400 per cent increase in apoptosis. The researchers suggest that several biochemical mechanisms may be responsible for the protective effects.
Lu YP, Nolan B, Lou YR et al. Proc Natl Acad Sci USA 2007;104:12936-41.