My doctor told me to avoid taking hot showers while i had a flare-up of my eczema. why is this?

Dries out your skin: Hot water is more likely to strip the natural oils off your skin. These oils are essential to keeping your skin healthy. Removing them leads to drier skin which can flare eczema. Using warm or cool water helps keep your skin protected.

Worsens dry skin: As dr benabio stated, hot showers will further dry out you skin and exacerbate eczema. The key is immediately moisturizing after showers and baths. Eczema skin is depleted of ceramides so picking a cream containing ceramides (ie. Cerave) and seal with a thicker emollient (ie. Certaphil or eucerin) on top will replenish some of the lost oils.

Dries out your skin: Frequent hot showers tend to worsen eczema. This is because hot water and harsh soaps remove the skin’s natural protective oils (think about how we clean greasy cooking pots with hot water and lots of soap). And be sure to moisturize. Patients with eczema have a break in their natural skin protective barrier and it is important to recreate that barrier with moisturizers.

Dryness, itching: Hot water not only washes away natural oils which maintains the moisture in the skin, but it also causes vasodilatation (opening) of the blood vessels of the skin and can flare the itching sensation. The increased itching leads to more scratching which further contributes to the flare and to the breakdown of skin barriers.

Agree with other mds: I would add that most soaps are drying, that pure soaps very efficiently remove natural oils from your skin, and that when you take your shower you should use a moisturizing soap like dove or cetaphil. Immediately moisturize upon getting out of the shower, and try to use the towel to gently pat dry, as rubbing removes even more oil.