Jell asked
I am 34 years old and for the first time in my life have developed dark patches of skin on my face, especially above my lip. I am in a hot country and exposed to the sun, but this is not new for me. The only difference to previous exposure is that I have been taking chloroquine prophylactically for the past 5 weeks now. I understand this can cause this hyperpigmentation. I wondered if I were to stop taking these if the patches would fade?
Answer
While uncommon, you are correct that chloroquine has been associated with various dermatologic adverse reactions.
There have been rare reports of many different types of skin reactions including:
- Erythema multiforme
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Exfoliative dermatitis,
In addition , pruritus (itchy skin) and pigmentary skin discoloration can occur, which seems to be what you described. While the itching typically has an onset within 6—48 hours of ingestion of the drug and affects the whole body, the other various skin reactions can really happen at any given time and seem to be more likely you are on the medication. Hyperpigmentation can be aggravated by exposure to ultraviolet light.
While there isn't much documentation on the resolution of these adverse effects, I did find information suggesting that they do get better and may completely resolve upon discontinuation of therapy. I would certainly follow up with your doctor regarding the side effects you are experiencing.
