Post Ambulatory Swollen Hands

© 2025 HMP Global. All Rights Reserved.
Any views and opinions expressed are those of the author(s) and/or participants and do not necessarily reflect the views, policy, or position of The Dermatologist or HMP Global, their employees, and affiliates.

Post ambulatory swollen hands (POTASH) is an idiopathic condition characterized by bilateral hand swelling associated with temporary functional impairment of the hands. Unassociated with systemic symptoms, the swelling starts after an ambulatory activity and usually resolves on its own.¹ We present a case of POTASH that began within an hour of ambulatory activity, with progression of the swelling during the duration of activity. The swelling was asymptomatic, with no associated angioedema, urticaria, or swelling in other locations. The distinctive impact was the temporary inability to use the right hand; specifically, the patient could not close his hand into a fist.² This positive fist sign was absent 2 hours after the activity was finished and the swelling of the hand resolved spontaneously.³

Case Report

A 65-year-old man developed asymptomatic swelling of both hands and all digits while walking a 13.1-mile race. The swelling initially began 1 hour after starting the race and progressively worsened as he continued walking (Figure 1). The swelling in the hands prevented the patient from being able to make a fist, indicating a positive fist sign (Figure 2). The swelling was not associated with any itching or pain. The patient did not have any associated systemic symptoms, including shortness of breath, palpitations, difficulty swallowing, or swelling elsewhere. The swelling in both hands and all digits spontaneously resolved, without any medical intervention, within 2 hours after he stopped ambulating (Figure 3). He was again able to clench his right hand into a fist, confirming a negative fist sign (Figure 4). The details of this report have previously been reported.³ These findings are similar to what has been described in 88% of the patients in Ravaglia et al.’s study that demonstrated resolution of symptoms within 1 to 2 hours after ending their activity.⁴

Discussion

POTASH was initially described as “big hand syndrome” in a paper analyzing hand swelling in people who walked in the park; some of these individuals were dog owners. The researchers found that approximately 1 in 4 people reported hand swelling. The incidence of hand swelling was greater in women and those individuals who walked less frequently.⁴ POTASH has also been described in participants in other outdoor activities such as hiking.⁵ Subsequently, a man has been reported who has recurrently developed swollen hands after participating in half marathons with no associated itching, pain, or other systemic signs.^1-3,6-8 In our case, the swelling began after the patient walked for 1 hour, it continued to increase for the next 3 hours that he participated in the race, and resolved without any intervention 2 hours after he completed the race and stopped ambulating.³

The term POTASH was established in an autobiographical case report in 2021.¹ The associated positive fist sign,⁶ which indicates an inability to make a fist, was also described to be associated with POTASH. Additional acronyms have since been established to describe the swelling associated with various activities of ambulation. These include hiking-associated swollen hands, running-associated swollen hands, and walking-associated swollen hands.⁸

The clinical differential diagnoses for POTASH include acute and chronic causes of swollen hands. Acute infectious causes for swollen hands, such as cellulitis or erysipelas, are often accompanied by tenderness and systemic signs of infection with fever or fatigue. Allergic- or immune response-mediated causes for swollen hands include contact dermatitis, urticaria, or angioedema; these can be suspected by accompanying pruritus or other systemic signs. Some of the etiologies for chronic forms of swollen or enlarged hands include acromegaly or lymphedema secondary to malignancy or infection. All these conditions do not resolve spontaneously and require medical intervention for alleviation, unlike POTASH.¹ POTASH-related swelling resolves within 1 to 2 hours after the activity has been completed, with the hand spontaneously returning to its morphologic appearance and functional baseline and the patient being able to create a fist, indicating a negative fist sign.

The pathogenesis of POTASH remains to be determined. A swollen hand associated with ambulation has not been evaluated with imaging studies or biopsy. Possible causes include vasodilatory mechanisms where increased blood and fluid flow to the periphery during activity and exercise to maintain physiologic homeostasis, resulting in swelling. Additionally, excess fluid intake during exercise was found to result in edematous swelling in various extremities and the eyelids in a study on ultra-distance cyclists.⁹ A more serious complication may include hyponatremia from exercise leading to fluid accumulation in the hands, although that finding is often associated with nausea, vomiting, or mental disturbance.¹⁰ Additionally, inherited or familial etiologies have also been suggested; however, genetic or biologic markers have not been established.⁷

Conclusion

POTASH is likely to occur more commonly than the number of published reports or studies suggest. It presents as asymptomatic swelling about 1 hour into an ambulatory activity, with an increase in swelling until the activity is stopped. Most patients recover spontaneously, without any additional treatment, approximately 1 to 2 hours after cessation of the activity. Further research is indicated to determine the incidence and pathophysiology of this condition.

Abhiraj Sanku is a student at Touro University California College of Osteopathic Medicine in Vallejo, CA. Dr Cohen is a professor at Touro University California College of Osteopathic Medicine and in the department of dermatology at University of California Davis Medical Center in Sacramento, CA.

Disclosure: The authors report no relevant financial relationships.

References

1. Cohen PR. Post ambulatory swollen hands (POTASH): an autobiographical case report. Cureus. 2021;13(11):e19312. doi:10.7759/cureus.19312
2. Cohen PR. Post ambulatory swollen hands (POTASH) revisited: post ambulatory hand swelling in a half marathon participant. Dermatol Online J. 2022;28(3). doi:10.5070/D328357794
3. Cohen PR. Post ambulatory swollen hands (POTASH): a case report. AME Case Rep. 2024;8:107. doi:10.21037/acr-24-101
4. Ravaglia FF, Leite MG, Bracellos TF, Cliquet A Jr. Postambulatory hand swelling (big hand syndrome): prevalence, demographics, and association with dog walking. ISRN Rheumatol. 2011;2011:659695. doi:10.5402/2011/659695
5. DesMarais M. Swollen hands when hiking or walking—the complete explanation. My Outdoor Basecamp. August 11, 2021. Accessed September 25, 2024. https://myoutdoorbasecamp.com/swollen-hands-when-hiking.
6. Cohen PR. Fist sign-associated post ambulatory swollen hands. JAAD Case Rep. 2023;36:116-118. doi:10.1016/j.jdcr.2023.04.018
7. Cohen PR, Cohen BS, Kurzrock R. An autobiographical case series of familial post ambulatory swollen hands (POTASH): hand swelling in a man and his sister while participating in a half marathon. Cureus. 2024;16(3):e55518. doi:10.7759/cureus.55518
8. Cohen PR. Running-associated swollen hands (RASH): case report of post ambulatory swollen hands (POTASH) in a man who completed a half marathon. Skinmed. 2024;22(6):479-481.
9. Gauckler P, Kesenheimer JS, Kronbichler A, Kolbinger FR. Edema-like symptoms are common in ultra-distance cyclists and driven by overdrinking, use of analgesics and female sex—a study of 919 athletes. J INT Soc Sports Natr. 2021;18(1):73. doi:10.1186/s12970-021-00470-0
10. Douglas I. Hyponatremia: why it matters, how it presents, how we can manage it. Cleve Clin J Med. 2006;73(Suppl 3):S4-S12. doi:10.3949/ccjm.73.suppl_3.s4