Neck rash

[GB13]

I was taking Bactrim for a staph infection and took it for 10 days as prescribed and finished my last dose on Monday, July 7.  Yesterday, July 12 I awoke to a slight itchying under my chin but didn't notice it for the rest of the day.  This morning however I woke myself up scratching.  I had raised bumps and slight swelling.  As the day has worn on, it has become noticably red and itching much more and spreading down onto my neck.  Could this be an allergic reaction to my taking the antibiotic, even though it has been almost a week since I finished my last dose?

[lenagj]

I think it could be a reaction you should ask your doctor because it sounds like you are allergic

[Dr_Aparna]

Hi,
This does seem to be an allergic reaction to Bactrim.The most common adverse effects are gastrointestinal disturbances (nausea, vomiting, anorexia) and allergic skin reactions (such as rash and urticaria).

What you have described sounds typically like hives.Hives are raised, often itchy, red welts on the surface of the skin. They are usually an allergic reaction to food or medicine.

When you have an allergic reaction to a substance, histamine and other chemicals are released into your bloodstream, causing itching, swelling, and other symptoms.

Treatment may not be needed if the hives are mild. They may disappear on their own. You can take  antihistamines like Cetrizine though it causes drowsiness, Loratidine is a better drug but it will take 2 days for it to be effective in treating the condition.
Apply Calamine lotion on the areas to relieve the itchy feeling.

ref:http://www.myonlinewellness.com/topic/adam1000845