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Speciality Spotlight
Dermatology
Sunscreen
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Sun Exposure
Naylor MF, Farmer KC [Univ of Oklahoma, Oklahoma City]
The Case for Sunscreens : A Review of Their Use in Preventing Actinic Damage and Neoplasia
Arch Dermatol 133: 1146-1154, 1997
Sunscreens are used to reduce or prevent ultraviolet [UV] rays from producing skin damage by their effect on DNA. Faulty DNA repair leads to neoplasia. Immunosuppression both local and systemic are other possible effects of UV light. Sunscreens however can produce skin alterations and by blocking sunlight lead to vitamin D deficiency. Their usefulness has been shown in melanoma prevention in Australia as indicated by lowering its incidence and mortality. Cutaneous cancer prone races and individuals should be thus protected. 2-Ethylhexyl p-methoxycinnamate has been mentioned as one of the sunscreens.
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Eberlein-Konig B, Placzek M, Przybilla B [ Dermatologische Klinik und Poliklinik der Ludwig-Maximilians-Universitat Munchen, Munich]
Protective Effect against Sunburn of Combined Systemic Ascorbic Acid [Vitamin C] and d-a-Tocopherol [Vitamin E]
J Am Acad Dermatol 38: 45-48, 1998
Antioxidants administered to reduce damage by free radical oxygen species is described. 20 normal white subjects including 4 women were given a minimal erythema producing dose of UVB light for 8 days [Age 23-46 years]. 12 areas of the lower back were thus studied. Using a double-blind method, either a placebo or 2000 mgm of vitamin C and 1000 IU of vitamin E were given orally during the study period of eight days.
The minimal erythema producing dose of UVB increased in the treated group from 80 to 96.5 mJ/cm2. In the controls reduction from 80-68.5 mJ/cm2 was observed. This fall is described as a priming effect.
These observations suggest that these vitamin supplements should be used to improve the effects of sunscreens rather as replacements.
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Fisher GJ, Wang ZQ, Datta SC, et al [Univ of Michigan, Ann Arbor]
Pathophysiology of Premature Skin Aging Induced by Ultraviolet Light
N Engl J Med 337 : 1419-1428, 1997
Sun exposure causes age related skin changes through ultra violet light effects. As changes in the dermis constitute the dominant effects these are described. 59 individuals belonging to the white race between the ages of 21 to 58 years comprised the research group. The buttock region was subjected to fluorescent ultra violet light exposure. Skin from normal and irradiated areas were studied. Itretinoin or its vehicle was applied and occluded for 48 hours before the ultra violet light exposure. As the effect of metalloproteinases had to be evaluated in situ, hybridization and in situ zymographic studies combined with immunohistology were done. Collagen degradation and levels of inhibitors of metalloproteinases-type I were assessed by radioimmunoassay and western blotting respectively.
Metalloproteinases causing collagen damage were elevated in irradiated skin. Tretinoin application prevented this. A rise in metalloproteinases calls for an inhibitor enzyme. This is not altered tretinoin.
Prevention of solar damage with proper advice is suggested.
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Therapeutics
Rosen T, Schell BJ, Orengo I [Baylor College of Medicine, Houston]
Anti – inflammatory Activity of Antifungal Preparations
Int J Dermatol 36: 788-792, 1997
This study compares the results of several antifungal creams with 2.5% hydrocortisone to determine their anti-inflammatory properties. UVB induced erythema of non-exposed sites were used for evaluation.
1% terbinafine, 1% ciclopirox olamine, and 1% naftifine hydrochloride were shown to possess anti-inflammatory effects that were greater than hydrocortisone. Other creams used were 2% ketoconazole, 1% oxiconazole nitrate and 1% econazole nitrate. These were less effective.
The use of an antifungal agent with anti-inflammatory activity thus takes care of the inflammatory component of fungal infections. Side effects of a steroid of the combination preparation are thus avoided.
