Recurring rash on shoulder

[zlora]

This rash is small (about the size of 2 quarters side by side), reddish and has little blister-like bumps. I first got it about 10 years ago. I appears once or twice a year and is either on the left or right side of my upper back near my shoulder near the armpit (but it isn't in my armpit .. it is actually on my back). I found a photo on a rash photo search on the internet which is attached here. It hurts and doesn't itch. It isn't herpes simplex; my doctor just had me get a blood test for this and it was negative. Besides, I've never heard of herpes simplex causing a rash on a persons back and nowhere else. What might this be?

[BhumikaMD]

Hi,

This could be sweat dermatitis, folliculitis, allergic reaction. In most individuals there are outbreaks of folliculitis from time to time.

Folliculitis is infection and inflammation of the hair follicles. The condition may be superficial (i.e., on the surface of the skin) or deep within the follicles.The most common cause of folliculitis is infection by the bacteria Staphylococcus aureus.

Folliculitis symptoms can appear independent of infection. Exposure of the skin to certain chemicals, especially oils and tars, can trigger an outbreak. People with depressed immune systems, diabetes, or obesity have a greater risk of contracting folliculitis than the general population.

Patients with chronic unresponsive folliculitis may require investigation into the source of the infection. S. aureus bacteria can live in the patient's nostrils, periodically triggering a folliculitis outbreak.

Individuals who are predisposed to folliculitis should be extremely careful about personal hygiene. Application of antiseptic washes may help prevent recurrences. A topical antibiotic cream, mupirocin (Bactroban®), has been effective at reducing bacterial colonization in the nostrils. It is applied twice daily for a week and is repeated every 6 months.

If there any of the mentioned medical causes then treating those will reduce the occurence of the condition.
http://www.dermatologychannel.net/follicle/folliculitis.shtml

Some stubborn cases of folliculitis have been responsive to laser-assisted hair removal. This process uses a laser to destroy the follicle. This reduces the scarring that results from folliculitis.

Let us know if you need any other information and consult a skin specialist if the lesion is persistent.

Regards.