The lesions from a yeast infection can typically be rubbed off while those of leukoplakia cannot.Treatment recommendations depend on features of the lesion. If abnormal cells are present or the lesion is small surgical removal is often recommended; otherwise close follow up at three to six month intervals may be sufficient. People are generally advised to stop smoking and limit the drinking of alcohol. In potentially half of cases leukoplakia will shrink with stopping smoking; however, if smoking is continued up to 66% of cases will become more white and thick. The percentage of people affected is estimated at 1–3%. Leukoplakia becomes more common with age, typically not occurring until after 30. Rates may be as high as 8% in men over the age of 70. Classification
Leukoplakia could be classified as mucosal disease, and also as a premalignant condition. Although the white color in leukoplakia is a result of hyperkeratosis (or acanthosis), similarly appearing white lesions that are caused by reactive keratosis (smokers keratosis or frictional keratoses e.g. morsicatio buccarum) are not considered to be leukoplakias. Leukoplakia could also be considered according to the affected site, e.g. oral leukoplakia, leukoplakia of the urinary tract, including bladder leukoplakia or leukoplakia of the penis, vulvae, cervix or vagina. Leukoplakia may also occur in the larynx, possibly in association with gastro-esophageal reflux disease.
Mechanism of action
As an antibacterial, dapsone inhibits bacterial synthesis of dihydrofolic acid, via competition with para-aminobenzoate for the active site of dihydropteroate synthase, thereby inhibiting nucleic acid synthesis. Though structurally distinct from dapsone, the sulfonamide group of antibacterial drugs also work in this way. As an anti-inflammatory, dapsone inhibits the myeloperoxidase-H2O2-halide-mediated cytotoxic system in polymorphonucleocytes. As part of the respiratory burst that neutrophils use to kill bacteria, myeloperoxidase converts hydrogen peroxide (H2O2) into hypochlorous acid (HOCl). HOCl is the most potent oxidant generated by neutrophils, and can cause significant tissue damage during inflammation. Dapsone arrests myeloperoxidase in an inactive intermediate form, reversibly inhibiting the enzyme. This prevents accumulation of hypochlorous acid, and reduces tissue damage during inflammation. Myeloperoxidase inhibition has also been suggested as a neuron-sparing mechanism for reducing inflammation in neurodegenerative diseases such as Alzheimers disease and stroke.Dapsones anti-inflammatory and immunomodulatory effects are thought to be its mechanism of action in treating dermatitis herpetiformis.Dapsone is an odorless white to creamy-white crystalline powder with a slightly bitter taste. History
Discovery
In the early 20th century, the German chemist Paul Ehrlich was developing theories of selective toxicity based largely on the ability of certain dyes to kill microbes. Gerhard Domagk, who would later win a Nobel Prize for his efforts, made a major breakthrough in 1932 with the discovery of the antibacterial prontosil red (sulfonamidochrysoidine).