Severe Rash on Armpits and Ribs Caused by What?

I have a bad rash/bug bites under my armpits.  It started out as what appeared to be a couple of bug bites, I slept once more on my bed and it got much worse so I completely changed sleeping locations, washed clothing, sheets, etc.  I thought all of the bites would heal up but they haven't causing me to think it might be something else besides bug bites.  There's so many under my armpits now it's hard to distinguish them, the circular bites that are healing up are leaving behind circles of very dry and slightly yellow skin.  The rash has now spread sporadically down my ribs with a larger concentration on my waist.  I haven't worn deodorant for about 1 week now...any suggestions on what it might be?

Additional information: Affected skin itches only mildly and feels hot/burns slightly when I take a shower.
                                 Mainly Dime-sized bites/circular patches of dry red skin (slightly yellow when healing up) with smaller rash all around them.

[Dr Santos]

Hi,

Hidradenitis suppurativa is a skin disease that affects areas bearing apocrine sweat glands and hair follicles such as the underarms. It presents with clusters of chronic abscesses or boils. Drainage provides some relief from pain. This may be triggered by stress, perspiration, hormonal changes, humid heat, and clothing friction. Treatments may vary depending upon presentation and severity of the disease. Have this evaluated further by your doctor for proper management.  Direct clinical examination of the lesions is important for proepr diagnosis. You can read more about this through this link: http://en.wikipedia.org/wiki/Hidradenitis_suppurativa

Take care and keep us posted.