To the Editor:

We read with great interest the article by Finckh et al (1) in which the authors reported an association between silica exposure from urban industrial occupations and the risk of systemic lupus erythematosus (SLE). As noted, the study population comprised economically disadvantaged communities in Boston neighborhoods, of which more than three-quarters of the female residents are of African American descent; as noted by the authors, persons with this ethnic background have an increased incidence of SLE compared with white individuals.

As appreciated by Finckh et al (1), it is difficult to control for all possible environmental and/or occupational exposures that may contribute to disease development. In this regard, we wish to draw attention to one possible exposure risk that may go unreported in studies of populations of color: the use of skin-lightening creams to reduce skin pigmentation. Almost half of such preparations have levels of mercury >1 ppm (mg/kg) (2), and topical application of the most commercially successful cream, sold in more than 35 countries, produces mercury levels in the kidneys of mice (3) equal to those found to accelerate idiopathic autoimmunity in lupus-prone strains (4). Significantly, the mercury levels achieved are equivalent to the levels found in humans with nonoccupational exposure (e.g., dental amalgams) (5). Although the offending cream, “Fair and Lovely” (produced by Hindustan Lever of India), has not been made accessible to American markets by the US Food and Drug Administration, it is easily purchased online and is legally available to millions of consumers in a multitude of other countries.

Adverse health effects due to the presence of mercury in skin-lightening creams have been known since at least the 1970s (6). The major consequence appears to be immune complex–mediated membranous glomerulonephritis (7) or an idiosyncratic nephrotic syndrome (8) associated with a minimal-change renal glomerular lesion that usually spontaneously remits upon discontinuing the offending cream (6). In the most recent case report, the patient had a low titer of antinuclear antibodies (9); this is not an uncommon finding following mercury exposure (10). Although data on occupational exposure have raised the suggestion of an association between mercury and SLE (11), to our knowledge no definitive studies have been performed. Animal studies, however, clearly document that the immunologic response to mercury is strongly controlled by genetic background and varies from minimal lymphoid alterations to overt systemic autoimmunity (12). Because low-dose mercury can accelerate lupus in susceptible mice (4), we believe the greatest effects of mercury-containing skin-lightening creams might be on age at onset and/or severity of disease as opposed to an increase in overall disease prevalence.

  • 1
    Finckh A, Cooper GS, Chibnik LB, Costenbader KH, Watts J, Pankey H, et al. Occupational silica and solvent exposures and risk of systemic lupus erythematosus in urban women. Arthritis Rheum 2006; 54: 364854.
  • 2
    Al-Saleh I, El-Doush I. Mercury content in skin-lightening creams and potential hazards to the health of Saudi Women. J Toxicol Environ Health 1997; 51: 12330.
  • 3
    Al-Saleh I, El-Doush I, Shinwari N, Al-Baradei R, Khogali F, Al-Amodi M. Does low mercury containing skin-lightening cream (fair & lovely) affect the kidney, liver, and brain of female mice? Cutan Ocul Toxicol 2005; 24: 1129.
  • 4
    Pollard KM, Pearson DL, Hultman P, Deane TN, Lindh U, Kono DH. Xenobiotic acceleration of idiopathic systemic autoimmunity in lupus-prone bxsb mice. Environ Health Perspect 2001; 109: 2733.
  • 5
    Nylander M, Friberg L, Lind B. Mercury concentrations in the human brain and kidneys in relation to exposure from dental amalgam fillings. Swed Dent J 1987; 11: 17987.
  • 6
    Barr RD, Rees PH, Cordy PE, Kungu A, Woodger BA, Cameron HM. Nephrotic syndrome in adult Africans in Nairobi. Br Med J 1972; 2: 1314.
  • 7
    Soo YO, Chow KM, Lam CW, Lai FM, Szeto CC, Chan MH, et al. A whitened face woman with nephrotic syndrome. Am J Kidney Dis 2003; 41: 2503.
  • 8
    Barr RD. The mercurial nephrotic syndrome. East Afr Med J 1990; 67: 3816.
  • 9
    Tang HL, Chu KH, Mak YF, Lee W, Cheuk A, Yim KF, et al. Minimal change disease following exposure to mercury-containing skin lightening cream. Hong Kong Med J 2006; 12: 3168.
  • 10
    Silva IA, Nyland JF, Gorman A, Perisse A, Ventura AM, Santos EC, et al. Mercury exposure, malaria, and serum antinuclear/antinucleolar antibodies in Amazon populations in Brazil: a cross-sectional study. Environ Health 2004; 3: 11.
  • 11
    Cooper GS, Parks CG, Treadwell EL, St Clair EW, Gilkeson GS, Dooley MA. Occupational risk factors for the development of systemic lupus erythematosus. J Rheumatol 2004; 31: 192833.
  • 12
    Pollard KM, Hultman P, Kono DH. Immunology and genetics of induced systemic autoimmunity. Autoimmun Rev 2005; 4: 2828.

K. Michael Pollard PhD*, Per Hultman MD, PhD†, * The Scripps Research Institute, La Jolla, CA, † Linkoping University, Linkoping, Sweden.