Although not all of these side effects may occur, if they do occur they may need medical attention. Check with your doctor immediately if any of the following side effects occur while taking hydroxychloroquine: Incidence not known Some side effects of hydroxychloroquine may occur that usually do not need medical attention. Methotrexate and plaquenil for ra Side effects stopping plaquenil Children should not take hydroxychloroquine for long-term therapy. Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your response to hydroxychloroquine. If you are taking hydroxychloroquine for a long period of time, your doctor will recommend frequent eye exams. SIDE EFFECTS. The following adverse reactions have been identified during post-approval use of PLAQUENIL or other 4-aminoqunoline compounds. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. An allergic skin rash that is caused by medication may last for weeks before the source is identified and usually resolves once the medication is stopped. The Wrap Up If you suddenly become itchy and begin to break out in hives anywhere on your body, you may be experiencing an allergic rash. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. These side effects may go away during treatment as your body adjusts to the medicine. How long for plaquenil rash to go away Allergic reaction to Plaquenil Lupus Forums at The Lupus Site, Side Effects of Plaquenil Hydroxychloroquine, Warnings, Uses Fibro and plaquenil Hydroxychloroquine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies, or to become more depressed. If you or your caregiver notice any of these side effects, tell your doctor right away. This medicine may cause hypoglycemia low blood sugar. Hydroxychloroquine Oral Route Precautions - Mayo Clinic. How Long Does an Allergic Rash Last? Healthfully. Hydroxychloroquine Side Effects, Dosage, Uses, and More. I have been on plaquenil for about 3 weeks and I am starting to get a itchy rash. It's pretty mild so far starting on my forearms and now on my chest a little and the rest of my arms. Has anyone else had this problem? Will it go away? I am going to call my doc tomorrow but just wanted someone's. Be patient. It is important that you always use sunscreen on this area and never to allow it to get sunburned. Additionally, consider seeing a dermatologist in another 5 weeks if the rash is not starting to get lighter. Even taking a picture and comparing every 4 weeks would give you a starting point. Well, unfortunately, there is no “magic” answer to this question. Since there are so many varieties of allergic reactions on the skin, the time that takes for them to go away will vary. So, let us go through the most common allergic skin conditions and the time it takes for them to go away.