I received a text the other night from Dr. Yaron Ivan (of PEM Rules fame): “Have you ever seen a patient like this?” PEM clinicians know that this is the type of text message that immediately grabs your attention.
Dr. Ivan told me about a case of a patient presenting with acute unilateral mydriasis – a “blown pupil.”
As you might expect, this immediately raised concern for a potentially life-threatening neurologic process. Neuroimaging was obtained. Laboratory testing was performed. Consultants became involved. A comprehensive workup ensued.
Everything was normal.
Dr. Ivan credits Dr. Makayla Romboy for eventually revealing the final diagnosis. The patient had recently started using prescription antiperspirant wipes for hyperhidrosis. After applying the medication, they inadvertently rubbed one eye before washing their hands.
The diagnosis?
Pharmacologic mydriasis from topical glycopyrronium (Qbrexza®).
Why Does This Happen?
Qbrexza® (glycopyrronium tosylate 2.4%) is an anticholinergic medication approved for excessive underarm sweating.
If a patient rubs one eye after applying the medication, glycopyrronium blocks muscarinic receptors in the iris sphincter muscle, producing pharmacologic mydriasis.
Because exposure is usually unilateral, the presentation can closely resemble a compressive third nerve palsy.
Naturally, I wanted to see what had been published about this presentation.
The first thing I found was a PEMPix case from 2020.
If you haven’t worked through it before, I highly recommend it. Like many of the great PEMPix cases, it walks readers through the differential diagnosis before revealing the unexpected culprit. There’s a particularly cool sliding graphic showing the patient’s pupils. It’s an excellent teaching exercise and perfectly illustrates why medication history matters.
Diving into the literature, here’s what the case reports reveal:
These patients are almost always otherwise well-appearing adolescents with…
Often, patients undergo CT scans, MRI, subspecialty consultations, or extensive laboratory evaluation before the medication exposure is recognized.
Enjoy this infographic produced with the help of ChatGPT.
HipPEMcrates Pearls
✅ Not every blown pupil is benign – consider the emergent causes first!
✅ Ask specifically about hyperhidrosis treatments – patients may not think of Qbrexza as a medication.
✅ Sometimes the most valuable diagnostic test isn’t a CT scan. It’s a careful medication history.
Check out the case reports:
Reversible anisocoria due to inadvertent ocular exposure to topical anticholinergic treatment for primary axillary hyperhidrosis (Pashaei-Marandi et al., 2019)
Don’t Sweat the Blown Pupil: Anisocoria in Patients Using Qbrexza (Al-Holou et al., 2020)
Anisocoria secondary to antiperspirant wipes in a pediatric population: a case series (Pecha et al., 2022)
Pharmacologic Mydriasis Secondary to Topical Glycopyrronium Tosylate Cloths: Clinical Characterization From a Multicenter Analysis (Kaufman et al., 2022)
Mydriasis and anisocoria in a pediatric hyperhidrosis patient with interesting findings in the family cat (Sandhu & Eisenstein, 2022)
Anisocoria in patients with hyperhidrosis: A case series for the primary care physician (Sasher et al., 2024)
Dr. Joshua Belfer, MD, is a Pediatric Emergency Medicine physician at the Children’s Hospital of Philadelphia, and is the Founder and Editor-in-Chief of HipPEMcrates. He can be reached at HipPEMcrates@gmail.com.
