Description
- Psoriasis is a chronic disease of the skin. It is characterized by recurring
remissions and exacerbations. Its lesions appear as erythematous papules (red elevated
area on the skin).1
- About 2% of the U.S. population is affected. Men and women are affected equally
and symptoms usually appear before 40 years of age.
Causes
- Certain individuals may have a genetic predisposition to develop psoriasis. The
cause has been linked to certain histocompatibility antigens and as such may be
an autoimmune process.1
- Flare-ups of psoriasis may occur unpredictably and may be associated with systemic
(whole body) and environmental factors.
At Risk
- Those with a family history of psoriasis are more likely to get this disease.
Prevention and Management
- There is no known way to prevent psoriasis.
- High fiber diets may reduce circulating endotoxins. Elevated endotoxins are positively
associated with psoriasis.2
- Fruits and vegetables (especially carrots) may alleviate psoriasis.3
- Low protein and low fat diets may help.
- One clinical observation is that psoriasis patients given a rice diet showed
a dramatic reduction in or disappearance of their skin lesions.4
- Patients with psoriasis may have lower levels of vitamin A. Vitamin A may inhibit
one of the rate limiting steps in the manifestation of the disease.5
- Low levels of folic acid are often found in psoriasis patients.6
- Oral calcitriol (1,25-dihydroxy vitamin D3) has been used successfully in the
treatment of psoriasis.7
- Selenium levels may be low. Selenium is important for the activation of an inhibitor
of the inflammation associated with psoriasis.8
Additional Information
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purposes only. USANA, Inc. makes no claim, actual or implied, regarding the content
or validity of the information obtained from these outside sources.
- http://www.psoriasis.org/
Abstracts
Barna M, Bos JD, Kapsenberg ML, Snijdewint FG. Effect of calcitriol on the production
of T-cell-derived cytokines in psoriasis. Br J Dermatol 1997 Apr;136(4):536-41. Although
the use of vitamin D analogues in the treatment of psoriasis has been important
new development, the mechanisms of action of these drugs are not fully understood.
Psoriasis results from hyperproliferation of keratinocytes, and various studies
attribute a crucial role to the locally infiltrating T lymphocytes. In an attempt
to add to the understanding of the mechanisms of calcitriol therapy, we determined
the effect of this drug on T cells by studying its effect on proliferation and
on the production of various cytokines by T-cell clones prepared from psoriatic
skin after non-specific activation with the combination of phytohaemagglutinin
(PHA) and phorbol myristate acetate (PMA). the addition of increasing doses (10(-9)-10(-5)
mol/l) of calcitriol to these T cells resulted in a dose-dependent inhibition in
lymphocyte proliferation and in production of the type 1 cytokines IFN-gamma and
IL-2, the type 2 cytokines IL-4 and IL-5. The general cytokines TNF-alpha and GM-CSF
were not significantly inhibited. These data suggest that calcitriol is involved
in the treatment of psoriasis via inhibition of the expansion, and cytokine production,
of skin-infiltrating T lymphocytes.
Corrocher R, Ferrari S, de Gironcoli M, Bassi A, Olivieri O, Guarini P, Stanzial
A, Barba AL. Gregolini L. Effect of fish oil supplementation on erythrocyte lipid
pattern, malondialdehyde production and glutathione-peroxidase activity in psoriasis
Clin Chim Acta 1989 Feb 15;179(2):121-31. Erythrocytes from psoriatic
patients have a significant increase in polyunsaturated fatty acids (p less than
0.001) especially in arachidonic acid (p less than 0.001). Glutathione peroxidase
activity, in both erythrocytes and platelets, was stimulated when compared with
normal cells (p less than 0.001, less than 0.02, respectively) and the production
of malondialdehyde was also increased in psoriasis (p less than 0.01). The level
of plasma selenium was significantly reduced (52.80 vs 72.49 ng/ml; p less than
0.001). alpha-Tocopherol and retinol were both normal in plasma of psoriatics.
After two months of fish oil supplementation, the erythrocyte lipid pattern was
changed, eicosapentaenoic and dochesaenoic acids substituting the arachidonate
in the membrane. A reduction in malondialdehyde (p less than 0.01), a prolongation
of bleeding time (p less than 0.05) and a further stimulation of glutathione-peroxidase
(p less than 0.001) in both erythrocytes and platelets was also found.
References
1 Rosenberg EW, Kirk BS. Acne diet reconsidered. Arch Dermatol 1981;117:193-95.
2 Naldi L, Parazzini F, Peli L, Chatenoud L, Cainelli T. Dietary factors
and the risk of psoriasis. Results of an Italian case study. Br J Dermatol 1996 Jan;134(1):101-6
3 Newborg B. Disappearance of psoriatic lesions on the rice diet. N Carolina
Med J 1986;47:253-55.
4 Fry L et al. The mechanism of folate deficiency in psoriasis. Br J Dermatol
1971;84:539-44.
5 Perez A, Raab R, Chen TC, Turner A, Holick MF. Safety and efficacy of
oral calcitriol (1,25-dihydroxyvitamin D3) for the treatment of psoriasis. Br J Dermatol
1996 Jun;134(6):1070-8.
6 White A et al. Role of lipoxgenase products in the pathogenesis and therapy
of psoriasis and other dermatoses. Arch Dermatol 1983;119:541-7.
