Hydroxychloroquine-Induced Skin Pigmentation
Yes, hydroxychloroquine (HCQS) can cause skin pigmentation, occurring in approximately 12-51% of patients on long-term therapy, typically appearing after several years of treatment. 1, 2, 3
Clinical Presentation
The pigmentation manifests as:
- Blue-gray or brown discoloration, most commonly affecting the lower extremities (shins), face, lips, and gums 1, 3
- Mottled, reticulated macular pattern that may appear on the upper back, shoulders, and temples 4
- Preceded by ecchymotic areas in 92% of cases, where bruising transitions to persistent pigmentation 2
- Median onset after 32 months (approximately 2.7 years) of treatment, though can occur as early as 3 months 3
Mechanism and Pathophysiology
The pigmentation results from HCQ binding to melanin in the dermis, combined with hemosiderin deposition from recurrent microtrauma and bruising. 4, 2
- Histopathology shows superficial dermal yellow-brown, non-refractile granular pigment that stains partially positive with Fontana-Masson (melanin) 4
- Iron concentration is significantly elevated in pigmented lesions (median 4115 nmol/g) compared to normal skin (413 nmol/g; P < 0.001) 2
- The drug concentrates in melanotic tissue, creating a substrate for pigment accumulation 5
Major Risk Factors
Concurrent use of anticoagulants or antiplatelet agents is the strongest independent risk factor for developing HCQ-induced pigmentation. 2, 3
- Oral anticoagulants and/or antiplatelet therapy significantly increases risk (p = 0.03) 3
- Higher blood HCQ concentrations independently associated with pigmentation 2
- Cumulative dose (median 361 g at onset) and duration of therapy 3
- Conditions predisposing to easy bruising present in 96% of affected patients 2
Clinical Management Algorithm
Prevention
- Maintain HCQ dosing at ≤5.0 mg/kg actual body weight to minimize all toxicities 6
- Screen for bleeding risk factors: anticoagulant use, antiplatelet therapy, thrombocytopenia, or coagulopathy 2, 3
When Pigmentation Occurs
- Document the pattern and distribution with photography 1
- Discontinue HCQ if cosmetically unacceptable to the patient or if associated with other toxicities 1
- Pigmentation gradually improves after drug cessation, though resolution may take months to years 1, 3
- Continue HCQ if pigmentation is mild and the drug provides significant therapeutic benefit, as this is not a dangerous toxicity 2, 3
Important Caveats
Do not confuse skin pigmentation with retinal toxicity—these are separate entities with different clinical significance. 7, 6
- Skin pigmentation is primarily a cosmetic concern, not a vision-threatening complication 2, 3
- Retinal toxicity requires different monitoring (baseline and annual ophthalmologic screening after 5 years) and has serious implications for vision 6
- The presence of skin pigmentation does not predict retinal toxicity risk 1, 2
HCQ-induced pigmentation is more common than historically recognized, affecting up to half of long-term users in systematic examinations. 3 Patients should be counseled about this potential cosmetic side effect, particularly those on anticoagulation or with bleeding tendencies. 2, 3