Sauna for cholinergic urticaria
Evidence review
Overview
Heat and sweating provoke cholinergic urticaria: a hot bath is one of the standard provocation tests, and hot-bath challenge has produced urticaria with angioedema in case reports. In the distinct subtype with reduced or absent sweating, a Japanese case series of 8 patients treated with daily half-body hot baths at 104-109 F for 3-7 days reported improvement in urticaria in half and in anhidrosis in 62.5%, without severe adverse events. A second Japanese retrospective review found improvement in 11 of 12 patients given regular sweating activities, including patients without anhidrosis, compared with 9 of 15 treated otherwise; the sweating method was not specified and one patient had anaphylaxis. The aim of these approaches is to restore sweating or induce tolerance; they come from small uncontrolled series and do not establish heat as a treatment for ordinary cholinergic urticaria.
Key findings
- Half-body bath 104-109 F, 30-60 min daily for 3-7 days in cholinergic urticaria with hypohidrosis or anhidrosis: urticaria improved in 4 of 8 (50%), anhidrosis in 5 (62.5%), pain in 3 (42.9%), no severe adverse events (Yoshida 2024)
- Regular sweating activities (method not specified): improvement in 11 of 12 (92%) and complete response in 8 (67%) vs improvement in 9 of 15 (60%) and complete response in 1 (7%) without; one case of angioedema and anaphylaxis (Minowa 2020)
- Hot-bath provocation is used to diagnose cholinergic urticaria (Commens 1978, PMID 626713)
Every study we reviewed
2 found benefit
Each study was checked on PubMed. The colored edge shows the direction of the result. The research library lists 8 studies on urticaria, across all heat and cold therapies, including case reports and older work not graded here.
Effects of hot bath therapy on cholinergic urticaria with hypohidrosis or anhidrosis.
Yoshida S et al. Eur J Dermatol. 2024. PubMed 39015961 · DOI
- Who
- patients with cholinergic urticaria with hypohidrosis or anhidrosis treated 2010-2022
- What
- hot-water immersion to the waist (half-body bath), 104-109 F
- Protocol
- 104-109 °F · 30-60 min · daily/wk · 3-7 days
- Measured
- pain, urticaria, anhidrosis
- Result
- Pain improved in 3 (42.9%), urticaria in 4 (50%) and anhidrosis in 5 (62.5%) patients, without severe adverse events.
- Limitations
- retrospective; uncontrolled; n=8; subtype with reduced sweating only; short follow-up
Regular sweating activities for the treatment of cholinergic urticaria with or without acquired idiopathic generalized anhidrosis.
Minowa T et al. Dermatol Ther. 2020. PubMed 32445244 · DOI
- Who
- Patients with cholinergic urticaria (78% men, median age 22), 14 with acquired idiopathic generalized anhidrosis (Sapporo, Japan)
- What
- Regular sweating activities (method not specified in the abstract), alone or with an H1 blocker or steroid pulse, in 12 patients vs other treatments without sweating therapy in 15
- Measured
- Symptom improvement and complete response
- Result
- With sweating therapy, 11 of 12 (92%) improved and 8 (67%) had a complete response (6 of 8 without and 2 of 4 with anhidrosis); without it, 9 of 15 (60%) improved and 1 (7%) had a complete response. One patient had angioedema and anaphylaxis during sweating therapy.
- Limitations
- Retrospective chart review; treatment not randomized and often combined with drugs; sweating method not specified in the abstract and may include exercise as well as heat.
Protocols used in the studies
Half-body hot baths at 104-109 F (40-43 C) for 30-60 minutes daily for 3-7 days, used as sweat-promoting therapy in the hypohidrotic or anhidrotic subtype.
What is still unknown
Controlled trials of sweat-promoting heat therapy in the hypohidrotic subtype; durability of response; whether sauna and hot-water immersion are interchangeable; safety in patients with heat-induced angioedema.
Safety
Cautions for sauna in this condition
- Heat and hot baths provoke lesions and itching in cholinergic urticaria (PMID 6615721); hot-bath provocation is a diagnostic test (PMID 626713).
- Hot-bath challenge has produced angioedema with urticaria, with a fall in peak expiratory flow in one patient (case reports, PMID 7295570); patients with a history of angioedema or wheeze with heat need medical supervision.
- Sauna heat can initiate cholinergic urticaria (review, PMID 3218900).
- Angioedema and anaphylaxis occurred in 1 of 12 patients during regular sweating therapy (PMID 32445244); induced sweating in cholinergic urticaria should start under medical supervision with emergency treatment available.
- See general-safety.
For clinicians
Suggested rationale
In small case series of cholinergic urticaria (Yoshida 2024; Minowa 2020), short courses of daily half-body hot baths or regular sweating activities were followed by improvement in many patients, particularly those with reduced sweating, but one patient had anaphylaxis; heat is also a trigger in this condition, so any sweat-inducing therapy should begin under supervision.
Suggested wording only. The treating clinician decides whether it reflects their clinical judgment for this patient.
Typical ICD-10 codes: L50.5. Examples only; the clinician assigns the code.
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