How Many Shades of Gray?
DISCUSSION
This type of bluish gray hyperpigmentation is an uncommon idiosyncratic effect of minocycline ingestion. Although long-term, high-dose use of the drug is usually responsible, hyperpigmentation has been reported with short-term use at relatively low doses. The most common presentation is in acne patients taking minocycline who notice color changes in their gums, sclerae, and nail beds.
Four distinct variations of hyperpigmentation have been described: a slate gray color on the face, a circumscribed distribution on arms and legs, a diffuse muddy brown discoloration on sun-exposed skin, and development on the thorax in old scars. In addition to affecting the skin, it can stain internal organs, heart valves, joints, and bones. Biopsy will reveal pigment granules in dendritic cells and extracellularly in the dermis.
In some cases, the discoloration can be permanent, but it typically clears upon cessation of the offending drug. In this particular case, the benefits of minocycline outweighed any concern about the dyschromia. Alternately, a 755-nm Q-switched alexandrite laser has been used successfully.
There are numerous causes of dyschromia, including other drugs (eg, antimalarials, amiodarones, gold and silver salts) and medical conditions (eg, Addison disease, onchronosis).
,TAKE-HOME LEARNING POINTS
- Though uncommon, there is an association between minocycline use and various forms of hyperpigmentation.
- The discoloration ranges from slate gray to muddy brown and can be seen on the sclerae, face, gums, trunk, and legs, as well as in scars.
- Though more common with long-term, high-dose use of the drug, dyschromia has been reported after as little as three months of therapy.
- Other drugs that can cause hyperpigmentation include antimalarials, amiodarone, and silver and gold salts.
- Most cases resolve upon cessation of the drug; for those that don’t, a 755-nm Q-switched alexandrite laser is effective.
