Tirzepatide and a rare skin rash: one case

A case report published in JAAD Case Reports in October 2026 describes a 29-year-old woman whose long-standing chest rash cleared during a five-month course of tirzepatide, the dual GIP and GLP-1 receptor agonist sold as Mounjaro and Zepbound. The rash was confluent and reticulated papillomatosis (CARP), and she lost 18 kg on tirzepatide before it was stopped^[1]. This is a single patient, so the honest way to read it is as a lead worth watching, not proof that tirzepatide treats the condition.

What the case actually describes

The patient had a several-year history of a rash on her chest that worsened during a pregnancy, and an exam found reticulated brown plaques across the intermammary area consistent with CARP^[1]. Between 2022 and 2025 she tried hydrocortisone cream, ketoconazole cream, topical tacrolimus, topical metronidazole, topical econazole and oral doxycycline. Each brought partial relief at best, and the rash came back once treatment stopped.

In July 2025 she started tirzepatide for weight management at 5 mg weekly, moving to 7.5 mg after a month. About one month in, after losing only 2 to 5 kg, her CARP improved substantially and stayed clear through November 2025^[1]. Tirzepatide was then tapered and stopped after five months of treatment because of hair loss. The rash stayed clear for two to three more weeks, then partially returned alongside 2 to 5 kg of regained weight, and by April 2026, after a 9 kg regain, she had a partial recurrence with mild itching.

Why researchers think weight loss might have helped

CARP, also called Gougerot-Carteaud syndrome, is an uncommon skin disorder that produces hyperpigmented, ring-patterned plaques, usually on the trunk. There is no single agreed cause: proposed triggers range from a bacterium called Dietzia papillomatosis to an exaggerated reaction to the yeast Malassezia furfur to a genetic keratin abnormality, and current treatment leans on oral tetracyclines, particularly minocycline^[3]. One thread in that list is metabolic. A 2017 case report described a 12-year-old girl with obesity who had both CARP and acanthosis nigricans, a different insulin-resistance-linked skin change, and both cleared together on oral minocycline, which the authors read as evidence the two conditions share a pathway^[4].

The case-report authors propose that insulin resistance and high circulating insulin can push skin cells to overgrow by activating insulin-like growth-factor signaling, and that a GLP-1 drug could ease CARP by improving insulin sensitivity as well as through weight loss itself. That framing is strengthened, in their reading, by the timing: the rash cleared after only 2 to 5 kg was lost, well before the bulk of the eventual 18 kg came off, which points toward a metabolic effect rather than weight loss alone^[1].

Tirzepatide is a dual agonist: it activates both the GIP receptor and the GLP-1 receptor, the two gut-hormone receptors that together drive insulin release, slow gastric emptying and signal fullness to the brain. Improved insulin sensitivity sits alongside weight loss as one of its known downstream effects, which is why the case-report authors single it out as the more likely explanation for a rash that improved before most of the weight came off.

What one case report cannot tell us

A case report describes one patient with no comparison group and no formal rechallenge. The partial recurrence after tirzepatide was stopped and weight was regained is suggestive, but it happened alongside a pregnancy history, several prior topical and oral treatments, and ordinary week-to-week variation in a condition already known to wax and wane. None of that proves tirzepatide, rather than something else changing in her routine, drove the improvement^[1].

Tirzepatide also is not approved for any skin condition. In the United States, Zepbound is labelled for chronic weight management and for obstructive sleep apnea in adults with obesity, and Mounjaro is labelled for type 2 diabetes; CARP appears nowhere on either label^[2]. The authors themselves call the evidence on metabolically targeted therapy for CARP limited and say more research is needed before drawing conclusions about GLP-1 drugs or other insulin-sensitizing agents as a treatment path.

What this means if you have a rash like this

The practical takeaway is measured. CARP is a diagnosis a dermatologist should confirm, because reticulated chest and back plaques can also be acanthosis nigricans, tinea versicolor or other look-alike conditions that call for different treatment. Minocycline remains the standard first step^[3], and this single case does not change that. Our tirzepatide overview covers the drug's approved uses and well-documented side effects, which are mostly gastrointestinal, not dermatologic. It is also worth noting that the reason treatment ended in this case, hair loss, is a separately reported reaction to GLP-1 drugs and had nothing to do with the skin condition being tracked, a reminder that real-world treatment courses stop for reasons that have little to do with the question a case report is trying to answer.

If you are considering tirzepatide for weight management and you also have a persistent skin rash, that is a conversation for your prescriber or a dermatologist, not a reason to start the drug off-label for the rash alone. This single case sits inside a wider, still-thin body of dermatology case reports on GLP-1 drugs, and none of it currently supports prescribing tirzepatide to treat a skin condition. This article is educational and is not medical advice. You can see how tirzepatide is regulated where you live on the tirzepatide page.