A close positive correlation between malodor and sweating as a marker for the treatment of axillary bromhidrosis with botulinum toxin A

Background: Botulinum toxin A (BTX-A) has been demonstrated to be only effective for some types of axillary bromhidrosis. It is necessary to explore the indications for BTX-A application. Methods: Sixty-seven consecutive outpatients with axillary bromhidrosis were recruited after informed content. Then, 50 U of BTX-A was injected intracutaneously into 20 different sites within each axilla. The follow-up was done every month and terminated when the malodor returned to the previous level. Results: Of 67 cases, 74.6% (50/67) had mild or moderate malodor, and 80.6% (54/67) experienced mild or moderate sweating. In 76.1% (51/67) of patients, there were a close correlation between malodor and sweating. After BTX-A injection, the malodor was eliminated in 73.1% (49/67) of patients. Logistic regression analysis revealed that the correlation between malodor and sweating differed significantly between the group that maintained no malodor after initial injection and the group that still exhibited malodor. Conclusion: BTX-A ameliorates malodor mainly by the inhibition of eccrine and apoeccrine sweating but no apocrine sweating. A close positive correlation between malodor and sweating is the indication for BTX-A treatment.