Hydrotherapy for Skin Conditions: Eczema, Psoriasis and Itch

Water Temperature, Itch and Eczema

The NHS says atopic eczema can be made worse by heat or changes in temperature. [1] For itchy skin in general, it lists cool or lukewarm baths or showers among things that may help, and advises not spending a long time in the bath or shower. [3] Moisturizer matters: emollients are best applied after a bath or shower, because that is when skin most needs moisture. [2] For the skin barrier, see dry skin and the skin barrier and eczema.

How Often to Bathe With Eczema

A systematic review of 13 prospective studies found the best bathing or showering frequency in atopic dermatitis remains unclear, but daily showers or baths were not associated with worse severity and should be permitted. [4] A 2026 American Academy of Dermatology guideline for children made conditional recommendations in favor of bathing, bleach baths and wet dressings, and strong recommendations for moisturizers. [5] Label: guideline-supported, with limited trial data.

Bath Additives, Bleach Baths and Hard Water

• Emollient bath additives. The BATHE trial randomized 483 children aged 1 to 11 in English and Welsh general practices to bath additives or none, alongside standard care. It found no evidence of clinical benefit from adding them. [6] It was open label, so participants knew their group. [6] This does not test leave-on moisturizers, which stayed part of care in both groups. No good evidence of benefit for bath additives in childhood eczema.
• Bleach baths. A review of 10 randomized trials (307 people, median 6 weeks) found bleach baths probably improve clinician-rated severity by a relative 22% in moderate-to-severe eczema, with adverse events mostly dry skin and irritation, and other outcomes uncertain. [7] Promising but limited, and a medically directed measure. This page gives no mixing instructions; use only what your clinician prescribes.
• Water softeners and hard water. A review found children in harder-water areas had higher odds of eczema (very low certainty), but no evidence that domestic water softeners improve severity in established eczema. [8] No good evidence of benefit for softeners as treatment.

Psoriasis: Spa, Dead Sea and Salt Baths

• A review of hydrotherapy, spa therapy and balneotherapy for psoriasis and atopic dermatitis analyzed 22 of 424 articles and called for more trials to explain how they might work. [9] A separate review of thermal mineral-water baths found eight studies (seven in psoriasis, one in atopic dermatitis) and said evidence of effectiveness is still limited and often of low quality. [10] An umbrella review described balneotherapy as an integrative support for some inflammatory skin diseases such as psoriasis. [11]
• A prospective cohort of 18 patients followed a 4-week individualized program of sun exposure and bathing at the Dead Sea in Israel. [12] It reported a large drop in psoriasis scores, but long-term disease control was not observed. [12] With no control group, and sun and bathing combined, the water's own effect cannot be separated.
• Clinic salt baths followed by ultraviolet B light were reviewed by Cochrane: eight trials, seven at high risk of bias in at least one area, and commercial spa or salt companies sponsored three. [13] The authors found low-certainty evidence and said they could not draw clear conclusions. [13] This is supervised phototherapy, not a home bath.

Label for spa and Dead Sea treatment: promising but limited. Proper evidence not found for plain home baths, Epsom salt baths or hot tub use as a treatment for psoriasis; we searched PubMed for bath, balneotherapy, salt-bath and spa trials in psoriasis and eczema. See Epsom salt baths and balneotherapy in Europe.

More on skin: psoriasis, itchy, red and sensitive skin and when to see a doctor about skin.