Control of skin infections by a combined action of ultraviolet A(from sun or UVA lamp) and hydrogen peroxide (HUVA therapy), with special emphasis on leprosy

Despite its abundance and certain therapeutic value, the importance of sunlight in the treatment ofinfectious skin diseases has not been fully exploited. One reason is that a sufficient amount of the damagingcomponents of sunlight (UVC and most UVB) cannot reach us and the band of UV that can reach (UVA) is a poor inactivator of living cells. UVA, however, can be deleterious to cells in the presence of sensitizers and a number of biological and chemical sensitizers have been identified which can inactivate microbes in the presence of UVA. Of several known agents, I have selected hydrogen peroxide (H2O2) as a UVA sensitizer and propose that acombined action of H2O2and UVA (HUVA therapy) can be utilized in controlling skin infections of various types.Of particular interest is infection by Mycobacterium leprae, which is known to affect many millions of humans globally. H2O2being relatively cheap (and UVA from the sun being free) the cost of application, particularly in third-world countries where leprosy is more common, would be low and therefore the treatment can be employed on a wide scale. A further reason for proposing the use of H2O2is that, out of several agents we have tested, this was found to be the most potent; it is also easily able to reach target sites, very cheap, relatively safe and there is no known microbial resistance to HUVA.