Bilateral Lower Extremity Discoloration
Am Fam Physician. 2019 Aug 15;100(4):239-240.
Author disclosure: No relevant financial affiliations.
A 68-year-old obese man presented for chronic disease follow-up. The patient's only concern was discoloration in his lower extremities that had developed over the previous three weeks. No other areas were involved, and he had no pain or itching.
His medical history included diabetes mellitus, hypertension, hyperlipidemia, and obstructive sleep apnea. His medications included hydrochlorothiazide, metformin, glipizide (Glucotrol), minocycline (Minocin), and pravastatin (Pravachol). Six weeks before presentation, he had right hip arthroplasty with postoperative joint infection that required prolonged suppressive antibiotic treatment. His vital signs were normal on physical examination. A diffuse area of hyperpigmentation was present on the lower legs and feet. The rash was bilateral with dark hyperpigmentation (Figure 1). Lower extremity distal pulses were normal.
Based on the patient's history and physical examination findings, which one of the following is the most likely diagnosis?
A. Addison disease.
B. Diabetic dermopathy.
D. Medication reaction.
E. Venous insufficiency.
The answer is D: medication reaction. Cutaneous hyperpigmentation is a recognized adverse effect of long-term minocycline therapy. The skin discoloration is largely cosmetic and not associated with other adverse clinical effects.1
The hyperpigmentation results from deposition of insoluble minocycline-iron complexes and can be blue-gray or muddy brown in color. The discoloration can occur on the face, arms, shins, or legs. The incidence of minocycline-related hyperpigmentation is highest in patients receiving long-term therapy for chronic infection (54%) or rheumatoid arthritis (36%). The incidence in those receiving low-dose minocycline for acne vulgaris is low (2.4%).2 In general, the risk of hyperpigmentation increases with longer duration of use.1,2
Referencesshow all references
1. Hanada Y, Berbari EF, Steckelberg JM. Minocycline-induced cutaneous hyperpigmentation in an orthopedic population. Open Forum Infect Dis. 2016;3(1):ofv107....
2. Schadler ED, Cibull TL, Mehlis SL. A severe case of minocycline-induced hyperpigmentation of the lower extremities. Cureus. 2018;10(5):e2672.
3. Alster TS, Gupta SN. Minocycline-induced hyperpigmentation treated with a 755-nm Q-switched alexandrite laser. Dermatol Surg. 2004;30(9):1201–1204.
4. Duff M, Demidova O, Blackburn S, et al. Cutaneous manifestations of diabetes mellitus. Clin Diabetes. 2015;33(1):40–48.
5. Jameson JL, ed. Harrison's Principles of Internal Medicine. 20th ed. McGraw-Hill; 2018.
6. Alguire PC, Mathes BM. Clinical manifestations of lower extremity chronic venous disease. Accessed July 15, 2019. https://bit.ly/2WHYGnq
This series is coordinated by John E. Delzell Jr., MD, MSPH, Associate Medical Editor.
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