beta-carotene and Dermatitis--Contact

This review deals with topical and systemic approaches for protection of human skin against the harmful effects of solar radiation. Two concerns about the deleterious effects of sun exposure involve: (1) acute effects (e.g., sunburn and drug-induced phototoxicity) and (2) potential long-term risks of repeated sun exposures leading to development of solar elastosis, keratoses, induction of both nonmelanoma and melanoma skin cancer, and alteration of immune responses and functions. Action spectra of normal and abnormal reactions of human skin to acute and chronic effects of solar radiation are presented with a view to helping the physician prescribe the appropriate sunscreens. Factors that influence acute effects of sunburn are reviewed. Various artificial methods effective in minimizing or preventing harmful effects of solar radiation, both in normal individuals and in patients with photosensitivity-related problems, are discussed. Emphasis is placed on the commercially available chemical sunscreens and their properties. Sun protection factor (SPF) values of several brand-name formulations determined with a solar simulator under indoor conditions (laboratory) and with solar radiation under natural, field conditions are presented. Factors responsible for variations of SPF values observed under indoor and outdoor conditions are reviewed. Systemic photoprotective agents and their limitations are outlined. The photobiology of melanin pigmentation (the tanning reaction) is briefly discussed, with emphasis on the dangers of using quick-tanning lotions for stimulation of the tanning reaction.

Topics: 5-Methoxypsoralen; Administration, Oral; Administration, Topical; beta Carotene; Carotenoids; Chloroquine; Dermatitis, Contact; Furocoumarins; Humans; Keratosis; Melanins; Methoxsalen; Nonprescription Drugs; Photosensitivity Disorders; Skin Neoplasms; Skin Pigmentation; Sunburn; Sunscreening Agents; Ultraviolet Rays

Double-blind, placebo controlled challenge tests with benzoic acid butylhydroxytoluene, butylhydroxyanisole, beta-carotene, beta-8-apo-carotenal, and sodium metabisulfite were made in 44 cases of chronic urticaria, 91 cases of atopic dermatitis, and 123 cases of contact dermatitis, as a comparison group. Positive reactions were seen in four patients, two of whom had urticaria, one atopic dermatitis, and one contact dermatitis. Two of these reactions were caused by the placebo, one in a patient with urticaria and the other in a contact dermatitis patient. For one patient who reacted to the placebo and one who reacted to benzoic acid, the challenges were repeated with positive results in both instances. In nine patients, equivocal test results were produced with all the active substances and the placebo, but in all nine cases, retesting 4 days later produced negative results. This suggests that common food additives are seldom if ever of significance as precipitating factors in chronic urticaria or atopic dermatitis.

Topics: Adolescent; Adult; Aged; beta Carotene; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Carotenoids; Child; Child, Preschool; Dermatitis, Atopic; Dermatitis, Contact; Double-Blind Method; Female; Food Additives; Humans; Male; Middle Aged; Prospective Studies; Sulfites; Urticaria

Reactive free radicals can be produced in the skin by the action of environmental factors, such as sun radiation and toxins. These radicals can damage the DNA, proteins and lipids of the living cells. The consequences can be skin aging, immune suppression and even skin cancer. Humans have developed a protective mechanism against the action of free radicals in the form of antioxidant substances. Several of these antioxidants cannot be produced by humans and have to be acquired via food, such as carotenoids. Optical, non-invasive methods, like resonance Raman spectroscopy, allow a qualitative and quantitative online detection of the kinetics of antioxidants such as carotenoids in the skin. By employing this method it has been shown that the uptake of carotenoids in food can lead to an accumulation in the skin. On the other hand, stress, illness and UV-radiation can reduce the concentration of antioxidant substances in the skin. A high concentration of antioxidant substances is protective and associated with a reduction in skin wrinkling.

Topics: Antioxidants; beta Carotene; Beverages; Biological Availability; Carotenoids; Dermatitis, Contact; Food; Humans; Lycopene; Nutritive Value; Signal Processing, Computer-Assisted; Skin Aging; Skin Physiological Phenomena; Spectrum Analysis, Raman; Sunburn; Ultraviolet Rays; Vegetables

Ultraviolet (UV)-induced immunosuppression is a critical step in UV carcinogenesis, permitting tumour outgrowth. We investigated the effect of dietary beta-carotene on UV suppression of contact hypersensitivity (CHS) to trinitrochlorobenzene (TNCB) in BALB/c mice. Mice were fed for 10-16 weeks chow alone or supplemented with 1% beta-carotene or placebo as beadlets. Serum beta-carotene was detectable by high performance liquid chromatography (HPLC) analysis only in beta-carotene-fed mice (2.06 +/- 0.15 micrograms/ml). Serum retinol was 0.22-0.27 micrograms/ml in all three groups. Mice (n = 41/dietary group) were irradiated with 0, 4.5, 9 or 18 kJ/m2 of UVB and the CHS response was measured. Decreased CHS responses were observed in all UV-irradiated groups compared with unirradiated controls. UV dose-responses for suppression of CHS derived by first-order regression analyses of plots of percentage suppression of CHS as a function of log10UV dose showed significant slopes (P < 0.02) for all three dietary groups and similar residual variances between groups, P > 0.05. The UV dose for 50% suppression of CHS was 6.3 kJ/m2 for control, 6.4 kJ/m2 for placebo, and 5.5 kJ/m2 for beta-carotene-fed mice. No significant differences in slopes or elevations between UV dose-responses were observed, P > 0.05. Skin levels of the initiator of UV-induced immunosuppression, cis urocanic acid, were determined by HPLC in mice given 0 or 9 kJ/m2 of UV (n = 28/dietary group). No significant differences were observed between dietary groups (range 35.2-41.1 ng/mg skin, P > 0.15) We conclude feeding beta-carotene to BALB/c mice does not alter susceptibility to UV immune suppression, in contrast to human studies.

Topics: Animals; Antineoplastic Agents; beta Carotene; Body Weight; Carotenoids; Dermatitis, Contact; Diet; Dose-Response Relationship, Radiation; Female; Immunosuppression Therapy; Mice; Mice, Inbred BALB C; Stereoisomerism; Ultraviolet Rays; Urocanic Acid; Vitamin A