Swimming pool - skin rash

Dear Dr. Rockoff,

I have been diagnosed 3 weeks ago with seborrhea (localised, chest and scalp only-  showed up last Autumn) - got prescribed a 0.1% steroid (Elocom in Europe) cream, Ketodar (2% ketoconazole shampoo) and Mycospor (bifonazole anti-fungal cream). I'm 31yo.
Although I have been swimming for as long as I can remember, only very recently I had the following problem, that could be related to seborrhea (?): after getting out of the water and a hot shower, in the following half an hour or so, I get non-itching, patchy redish rashes on both of my upper arms (the outer side of biceps going over to triceps).
My skin becomes very dry anyway due to the chlorine, but I can still see that these patches are drier/flakier. They are not raised above the skin, are perfectly flat and only itch if rubbed with towel etc. Puzzling that the thinner skin under the arm has no problem, and this shows on the outer parts.
They go away within hours, but I can see the patches being drier than the skin around them - and eventually it subsides with moisturising. Maybe the skin  has an underlying problem now that is brought to surface by the chlorine and made visible? But I never had this problem up 'til now, using the same pool.
I am afraid it could be spreading eczema-like irritation (?) related to seborrhea (?). Will those patches become worse and maybe won't tan any more? in which case I'm in for a Summer nightmare. Not sure if I should touch it with Elocom or the anti-fungal cream that I still use.
Also, the scariest thing is that maybe I have to quit swimming if this aggravates some latent or new skin problem - this would be very depressing.
Therefore any advice would be very gratefully received, thanks in advance.

[Alan Rockoff, MD]

I've never had to advise patients to quit swimming, no matter how sensitive their skin, so I wouldn't worry about that.

Some people get small hives after exposure to hot water or after sweating.  I'm guessing that that's what you have.  You may also be noticing extra redness on the seborrheic areas, only because water and warmth highlight redness, whatever the cause.

Try taking a non-sedating antihistamine (Claritin in non-prescription in the US) one hour before showering, to see if that works.

If you can't arrange top have a dermatologist see it before it fades, you can try photography, though such a rash may be hard to photograph.

Ultimateley, you may end up doing what most of my patients who have this do--just ignore it.  But try getting a dermatologist to evaluate it if you can.

Take care.

Dr. Rockoff

[mangocheer]

A related discussion, will I ever be able to go in a swimming pool? was started.

[Jimmy51]

A related discussion, Rash after swimming in pool was started.