Pigmentation Abnormalities

Pseudocatalase Cream for Vitiligo

Vitiligo is a spontaneous irregular depigmentation of skin. Patients with vitiligo have low catalase levels in their epidermis with high levels of hydrogen peroxide. Pseudocatalase cream is an externally applied UVB-activated product that can lead to recovery of the oxidative damage in the epidermis and remarkable repigmentation.

Skin Pharmacol Appl Skin Physiol 1999 May-Jun;12(3):132-8
Successful treatment of oxidative stress in vitiligo.
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J Pathol 2000 Aug;191(4):407-16
Melanocytes are not absent in lesional skin of long duration vitiligo.
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J Investig Dermatol Symp Proc 1999 Sep;4(1):91-6
In vivo and in vitro evidence for hydrogen peroxide (H2O2) accumulation in the epidermis of patients with vitiligo and its successful removal by a UVB-activated pseudocatalase.
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Dermatology 1995;190(3):223-9
Treatment of vitiligo with a topical application of pseudocatalase and calcium in combination with short-term UVB exposure: a case study on 33 patients.
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Topical Phenylalanine for Vitiligo

Melanocytes may still be present in long-standing (>25 years) depigmented skin of patients with vitiligo. L-phenylalanine uptake and turnover in the pigment forming melanocytes is vital for initiation of melanogenesis. Phenylalanine hydroxylase activities increase linearly with inherited skin color yielding eightfold more activities in black skin compared to white skin.

Camacho and Mazuecos performed an uncontrolled retrospective survey of a group of 193 patients (171 participants after screening) with evolving vitiligo who were treated with oral (50 or 100 mg/kg daily) and topical (10% gel) phenylalanine plus sun exposure. When the study closed, 100% repigmentation was achieved in 122 patients on the face, 35 on the trunk, and 33 on the limbs. Patients who were treated during the months of high solar radiation (and therefore also used the topical phenylalanine) achieved greater repigmentation. No side effects were reported.

Arch Dermatol. 1999;135:216-217
Treatment of vitiligo with oral and topical phenylalanine: 6 years of experience.
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J Drugs Dermatol 2002 Sep;1(2):127-31
Oral and topical L-phenylalanine, clobetasol propionate, and UVA/sunlight--a new study for the treatment of vitiligo.
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Mol Genet Metab 2005 Dec;86(4):27-33
Decreased phenylalanine uptake and turnover in patients with vitiligo.
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Researchers concluded that "although hydroquinone showed a better response, ascorbic acid may play a role in the therapy of melasma as it is almost devoid of side-effects; it could be used alone or in combination therapy."

Int J Dermatol. 2004 Aug;43(8):604-7.
A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma.
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Melasma is a circumscribed brown macular hyperpigmentation of areas of the face and neck that are exposed to light, and is aggravated by sunlight, birth control pills, and pregnancy. This study demonstrates that a cream containing hydroquinone, glycolic acid, vitamins C and E, and sunscreen is a safe and effective treatment therapy for melasma.

Int J Dermatol. 2003 Dec;42(12):966-72.
Safety and efficacy of 4% hydroquinone combined with 10% glycolic acid, antioxidants, and sunscreen in the treatment of melasma.
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The antioxidant N-acetyl cysteine (NAC) has an antiproliferative effect on human keratinocytes and NAC has been used topically to satisfactorily treat lamellar ichthyosis.

Lancet. 1999 Nov 27;354(9193):1880.
Topical N-acetylcysteine for lamellar ichthyosis.
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Topically applied NAC can prevent skin irritation resulting from radiotherapy and protects from sun-induced erythema.

Semin Oncol. 1983 Mar;10(1 Suppl 1):86-92.
Topical use of N-acetylcysteine for reduction of skin reaction to radiation therapy.
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