cutaneous hyperpigmentation is a recognized adverse effect of chronic minocycline use occurring in up to 50% of patients , . in a recent study performed at the mayo clinic , 54% of 291 patients receiving long - term minocycline suppression for orthopedic infections developed some degree of hyperpigmentation after a mean follow - up of 4.8 years . in this cohort ,
factors associated with minocycline - induced cutaneous hyperpigmentation ( mich ) include a history of vitamin d deficiency , presence of a shoulder prosthesis , noncirrhotic liver pathology , and use of a concurrent medication ( e.g. , calcium channel blocker ) also known to cause hyperpigmentation .
mich is not associated with adverse clinical effects , and it is mostly cosmetic in nature .
we herein present a rare case of extensive skin hyperpigmentation involving both lower extremities in a patient receiving long term minocycline .
in june 2016 , a 76-year - old male with a past medical history significant for nephrolithiasis and diverticulitis , presented to the authors institution with extensive hyperpigmentation involving both lower extremities .
he underwent a left total knee arthroplasty in 1988 at an outside institution and underwent revision surgery in 1992 . in 2001
, he underwent a second revision for fractured patella that was complicated by an infection with a coagulase - negative staphylococcus .
he received six weeks of treatment with parenteral vancomycin followed by oral trimethoprim - sulfamethoxazole .
operative cultures from the knee grew enterococcus sp . , prevotella sp , viridans group streptococcus , as well as candida parapsilosis . after completing antimicrobial treatment with vancomycin , ertapenem and fluconazole
, he underwent reimplantation using a rotating hinged knee arthroplasty in september 2005 ( fig .
since that time , the patient was maintained on oral minocycline chronic suppression . in 2010
he uses a brace as well as a cane to ambulate . at a follow - up in february 2012
when he was seen again in june 2016 , there was extensive blue - gray pigmentation in both cheeks and in the lower extremities ( fig .
2 ) , as well as sub - ungual blue - gray pigmentation in both hands ( fig .
there are three types of pigmentation patterns that can result from taking minocycline for long periods of time .
type i is a blue - gray pigmentation occurring around areas that were previously inflamed .
type ii has the same appearance as type i and covers areas of normal skin such as the anterior shins , arms , and ankles .
type iii is a muddy brown pigmentation usually occurring on areas of the skin that are exposed to the sun .
the blue - gray pigmentation is due to the deposition of iron within the dermal macrophages .
the diffuse hyperpigmentation seen in the patient presented in this case report includes both types i and ii . blue - gray pigmentation is clearly seen around the scar on the left knee from his knee replacement surgery ( type i ) .
hyperpigmentation is also distinctly seen on the shins of both legs and around the ankles of the patient ( type ii ) .
hyperpigmentation is predominantly seen with minocycline and less likely to occur with other tetracyclines such as doxycycline .
minocycline is five times more lipophilic than doxycycline ; hence , central nervous system adverse events are more common with minocycline .
although doxycycline may have a higher incidence of gastrointestinal upset and photosensitivity , minocycline has an increased likelihood of severe and permanent cosmetic adverse events and central nervous system adverse events . in the study of orthopedic patients on long - term minocycline suppression ,
these side effects are an addition to gastrointestinal adverse effects that can also occur with minocycline . in the absence of data to show that minocycline is superior to doxycycline for long - term suppression of infections including orthopedic infections , the authors propose that doxycycline be looked upon favorably when chronic use is indicated .
 cutaneous hyperpigmentation is a recognized adverse effect of chronic minocycline use occurring in up to 50% of patients . in this report 
 we present a rare case of extensive skin hyperpigmentation involving both lower extremities in a patient receiving long term minocycline . 
 the patient was receiving minocycline as suppression for chronic prosthetic joint infection . 
 risk factors associated with minocycline - induced cutaneous pigmentation ( mich ) will be reviewed . 