Gary asked
I had strep and took amoxicillin. Then, after seven days or so, my skin itches and white bumps show up then go away.
Answer
It is a fairly common side effect of amoxicillin to have a rash or hives form after taking the medication for a few days. Fortunately, this type of reaction is typically less serious than immediate reactions (occurring within an hour or two of initial dosing).
Rashes that appear after being on amoxicillin for a few days can be classified a few different ways, but are generally referred to as idiopathic reactions. In fact, the reported incidence of these types of reactions is between 1-5% of individuals taking amoxicillin. Idiopathic reactions most commonly occur after 72 hours of amoxicillin exposure and primarily involve the upper extremities and trunk of the body.
Late Rash While Taking Amoxicillin
If you do get a late forming rash or hives while taking amoxicillin, it can be treated with antihistamines to help relieve itching as well as topical preparations such as Sarna or moisturizing lotions to soothe the area.
Most sources don't consider late reactions to amoxicillin as a true allergy, one that would preclude the use of similar antibiotics again. It is important to let your doctor know the reaction you are experiencing but don't be surprised if they prescribe similar antibiotics, such as penicillin or ones from the cephalosporin class. In addition, there are rare cases where rashes can progress to more serious medical problems and your doctor needs to be aware of your symptoms.
If the rash you are experiencing is a late reaction to amoxicillin, it should begin to clear in just a few days. If it appears to be getting worse or is not resolving, be sure to see your doctor for appropriate treatment. They may even perform a penicillin skin test, just to rule out the chance you may have more serious reactions in the future.
