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Have itchy rash on upper arm and back. Rashes turning into blisters. Any ideas?

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Practicing since : 2003
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Hello. I have a very itchy rash, particularly on my upper arms and somewhat on my back. I first noticed a very itchy redness on my hands, mostly between my fingers and on my knuckles. Those turned into small bumps and have since almost dissapeared (lasted about a month on-and-off). They started as red little spots, and are now raised little bumps, some of them appear to have white heads on them (blister-like). It has spread somewhat over the last few days to my back (to a lesser degree) and further around my arms. It is mainly limited to my upper arms, but there is some itchiness randomly on my legs and other areas. Any ideas?
Posted Mon, 15 Apr 2013 in Skin Hair and Nails
Answered by Dr. Tanusree Biswas 2 hours later

Thanks for sharing your concern with us.

Firstly, if we have to analyze the rash that was on and off appearing like blisters in between your fingers, I think they may be:
1) Pomp holyx or dyshidrotic eczema: this is form if endogenous excema. It shows s very itchy deep seated blisters on the hand; like fingers and palms
2) Scabies infection. This is a parasite infestation due to what we commonly call as 'itch mite'.

The rash you have now does not seem to any related to any of the above since it is only on the back and upper arms.

Considering the site, and the morphology of the current eruptions, possibility is:
Acne Vulgaris: or pimples in simple terms, they may present in the upper arms and back. They are itchy in some people and may/ may not be accompanied by acne on face. Morphologically they have whiteheads/blackheads, papules, pustules or deep seated nodules.

If you feel the rash is in a generalized distribution, meaning that there are eruptions on legs, please send in a photo of the same. You can mail them to


with subject as 'ATTN DR.TANUSHREE BISWAS'

Usually the fungal infection of groin does not give rise to any similar symptom. But sometimes if you have a chronic infection, you get a generalized itchy eruption known as 'id reaction' due to a hypersensitivity phenomenon.

I will be able to help you better, if you can let me know the following:
Did the rash on back/ arm appear suddenly or did it come up gradually over a period of time?
Do you have acne on the face?
Do you still have the groin infection or it has completely resolved? Did you take any treatment for that?

Hope the above information is helpful to you. Since we are probably looking at 2 things that mite co exist, it is good to have an examination with your dermatologist and confirm the diagnosis and start appropriate treatment.

I will be happy to answer your follow up queries.

Best Wishes,
Above answer was peer-reviewed by
Follow-up: Have itchy rash on upper arm and back. Rashes turning into blisters. Any ideas? 27 minutes later
Thanks for the response. The rash is almost exclusively on my upper arms, with a very limited amount on my upper back and a couple localized areas. The rash on my arms appeared about 3 days ago and worsened steadily since then. It now shows signs of some of the bumps blistering.

No acne on my face. My groin infection is almost fully cleared up, but not 100%, as I am still taking lamisil for it.

I had wondered about scabies, but why would it be so localized.

Any help is appreciated
Answered by Dr. Tanusree Biswas 23 minutes later

Thanks for following up.

You are right in scabies being a localized infection. However some cases are not very generalized and may present as limited sites being affected. Something which can be easily ruled out by observing the scrapings under a microscope to look for scabies mites or eggs.

Some people do have acne in the trunk only. The lesions might progress to become pustular if left untreated.
If you are applying any thick creams/lotions/oils in the body, you will need to stop them. Although the etiology is hormonal, some occlusive applications increase comedone formations which is an integral part of acne.

You should confirm the diagnosis with your dermatologist for the arm rash. When treatment is started early, the scarring is minimal.
For the treatment of acne, topical /oral antibiotics and retinoids are used.

Itching is a symptom and can be controlled by oral anti histaminic medications alone.

You should complete the course of Lamisil as well; this helps you to eradicate the groin infection which otherwise might persist.

Hope this is helpful to you.
Will be happy to answer if you have questions.

Wishing you good health,
Above answer was peer-reviewed by
Follow-up: Have itchy rash on upper arm and back. Rashes turning into blisters. Any ideas? 4 hours later
Thanks. One follow-up note ... I was doing some research of my own and saw a picture of Keratosis Pilaris ... it looks exactly like what I have, except that mine is very itchy.

Do you know any good ways to treat this condition?

Answered by Dr. Tanusree Biswas 1 hour later
Thanks for following up..

Keratosis Pilaris is a possibility in the upper arms ; however ,they are not so itchy usually and also do not form pustules .They are keratotic or hard papules on the follicles. Usually they are slower in onset and would not arise so many in just 3 days.

Treatment of Keratosis Pilaris is with:
Salicylic acid ointments
Retinoids (topical)

Hope this is helpful.

Best Wishes,
Above answer was peer-reviewed by
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