FREQUENTLY ASKED QUESTIONS ABOUT ANTIBIOTIC THERAPY

5. WHAT IS HYPERPIGMENTATION?

Minocycline can cause discoloration of the skin anywhere on the body. This is called hyperpigmentation. Large daily doses of ascorbic acid (vitamin C) may prevent this phenomenon. (Bowles WH, Baylor College of Dentistry, Texas A&M University System Protection against minocycline pigment formation by ascorbic acid, J Esthet Dent, 10(4):182-6 1998)

Dr. A. Robert Franco, a rheumatologist practicing in Riverside, California, says that hyperpigmentation occurs in about 10% to 20% of patients taking minocycline (Minocin) on a daily basis and over one year. Occasionally it may appear earlier. It occurs less frequently with patients taking Minocin on a three times per week basis. It may be necessary to switch to another antibiotic. It is usually reversible after discontinuation of the medication, but fades slowly and sometimes not completely.

Dr. Pnina Langevitz in Israel has done three double-blind studies on the use of minocycline in rheumatoid arthritis with some patients on the medication over 5 years. The following is from Langevitz et al - Minocycline in Rheumatoid Arthritis; Isr. J. Med Sci 1996;32:327-330. 'We also observed skin hyperpigmentation in about one third of our patients as a late complication of the therapy. Minocycline related hyperpigmentation of the skin is a well known complication of this agent and can be subdivided into three categories. The first is characterized by dark black-blue macules localized at sites of cutaneous inflammation. . . . . . . . . . . The second type is a more diffuse hyperpigmentation, predominantly on the lower extremeties and on areas exposed to sunlight. . . . . . . . The third form of minocycline-induced hyperpigmentation is the 'muddy skin syndrome' Đ a dark brown-gray discoloration of the skin generalized over the body, less prominent in non exposed areas. The high incidence of skin hyperpigmentation in our group of patients is probably due to the longer follow-up period than that in other groups, and to sun exposure.' (Patients in this study were on 100 mg. of minocycline twice daily.)