Question: 10 years ago I had a small bump removed from my back, near my spine. It was mostly painless but eventually became painful after years. It was marble sized or less. I believe if was diagnosed as a cyst, but this removal was done at an urgent care clinic, so I’m not sure if any pathology was done.

Recently, within the past few months, I’ve felt it grow back. During the past few weeks I’ve noticed that it grew back and has become painful when pressure applied to it. I went to the same urgent care clinic (too difficult to get a dermatologist appointment). The doctor said it was probably a cyst, cut into it, said it was “a little but pusy, “packed” it, applied a dressing, gave me a prescription for a 10 day course of Bactrim, said to return in a few days to have the packing removed, and advised to follow up with a dermatologist or a surgeon in case the “core” was not removed.

So, I have several questions.

1) Based on this description, does this indeed sound like a cyst? (I will try to attach a photo of the pre-removal lump). In other words, should I be concerned that it is something cancerous like a liposarcoma?

2) Is the fact that the original procedure, 10 years ago, was also performed at urgent care clinic a possible reason why the growth grew back? That is, the “core” was not removed?

3) Regarding Bactrim. I am not sure if i have a sulfa-drug allergy. I don’t believe I do, and I may indeed have taken a sulfa drug before without incident. I simply can’t remember. Is this drug truly necessary under the circumstances? I am traveling out of the country to propose to my girlfriend in less than a week—I am concerned that I will develop a rash by then and, obviously, this will not be ideal for the occasion (or for international travel).

Thanks in advance.

Thanks very much for your quick response.

I’ve already taken a single dose/pill of the Bactrim. If I discontinue now, would this reduce the likelihood of adverse reaction?

Additionally, are these other classes any less effective for this purpose?

And on the other hand, what is the real risk of taking no antibiotic at all? I would prefer to not need anything due to the general antibiotic GI side effects. If I take nothing, can I still minimize risk of infection?