Mystery Rash

[Davisgirl2]

For the past eight years I have had several mysterious rashes.  Doctors have been unable to determine why.  The only answer I have recieved is that I appear to be allergic to something.  The rash begins as a small red raised very ithcy area, not really a welt but, similar.  It grows to a large red area the size of say the palm of a hand, then it begins to lesson in the middle, but spreads out circularly.  It eventually tollay heals in the middle and the rash continues to spread circularly, up and down the limb.  I have had this on my neck near my collar bone (orginal site) eight years ago, on both legs, and on my arms.  At this time I have a rash on my left arm, under side and on my trunk on the rib area.  Yes, they do correspond in area.  The rash looks like a contact dermititis would look.  I use benadryl and steriodal cream with moderate success.  I have been perscribed steriods in the past but, this nearly threw me into diabetes so I would like not to take them again.  Both of my sisters have Thyroid desease and at one time had terribe rashes with this.  I have had thyroid test, and a thyroid antibody test about 3 years ago but, they were negative.  I have also tested negative for Lupis.  These rashes come and go (at times staying for up to a year and then gone a year.)  Last December I developed a rash on my right arm and both thighs which stayed until April.  Within the last month I have developed the rash on the left arm and rib area.  I am an R.N. and have tryed my best to get a diagnosis with little to no success.  I am currently taking daily Metformin, Benadryl, prilosec, and a birth control pill.  I was taking none of these when this all began, and have only taken most of these for about a year.  Strangely enough I wonder if it is somehow hormone related as all this began with perimenapausal symptoms.  I was pregnant at 43 and all symptoms disapeared for about 2 years.  Prior to the pregnancy had been my first "circular" rash.  Any suggestions for possible testing etc.  will be greatly appreciated.  (I have tested negative for HIV,  & Hep. C.)  
Thank you in advance for any help you may give.
Kim

[Dr_Aparna]

Hi,
This seems to be a case of hives.Hives are red, itchy welts or swellings on the skin that often come in clusters. They sometimes have a light red or pale center surrounded by a darker red area around the borders -- a marking resembling tiny bull's eyes -- but may simply look like large red circles. In doctor speak, hives are known as "urticaria."

Hives can appear anywhere on the body, cropping up either in one small area or covering large patches of skin. They most often occur as part of an allergic reaction. No one lesion lasts more than 24 hours, but new ones may continue to appear until the condition resolves.

Hives usually appear suddenly and go away on their own in a matter of days, hours, or even minutes. Chronic hives, however, can last for six weeks or more. Certain people have recurring outbreaks of hives for months or even years, and it's sometimes difficult to pinpoint the exact cause.
When an irritant comes into contact with your body, your immune system sends chemicals, including histamine, to fight it. The sudden spike in histamine levels can cause an outbreak of hives in the upper layers of the skin. Hives are often caused by a hypersensitivity to:
•Foods (commonly eggs, shellfish, nuts, berries, dyes, or other additives)
•Drugs (any drug can touch off an allergic reaction, although allergies to penicillin, sulfa, and aspirin are especially common)
•Pollens and plants (nettles, poison ivy, poison oak, and so on)
•Animal fur
•Insect bites or stings
•Exposure to heat, cold, or sunshine
Other potential triggers include physical exertion or exercise, stress, illness, chemicals, cosmetics, textiles, and pressure from materials rubbing against the skin.
Typically, chronic hives go away on their own, whether you treat them or not. About half of all chronic cases clear up within a year, though some cases can take as long as five years. A very small percentage of people are plagued by hives for even longer.
There are some rare immune disorders that can cause hives, but only a comprehensive exam can determine that. If you have hives that linger for six weeks or more, ask your primary care doctor for advice. He or she may refer you to a specialist such as an allergist or immunologist. They can do skin or blood tests to help determine what foods or other substances trigger your hives.
ref:http://www.myonlinewellness.com/topic/hivestreatment