An Early Phase 1 interventional study of Doxycycline and Ivermectin Topical in Rosacea, sponsored by Johns Hopkins University. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years to 99 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-08.
Sponsored by Johns Hopkins University · Early Phase 1, Interventional, and Basic science
The skin and gut microbiome of rosacea patients differs from individuals without rosacea and that the microbiome suffers from unique derangements in rosacea patients following antibiotic therapy.
This study was proposed to examine microbial signatures of the skin and gut microbiome in patients with moderate to severe rosacea and to identify differences between microbe communities in patients with rosacea and volunteers without rosacea using 16S ribosomal ribonucleic acid (rRNA) polymerase chain reaction (PCR) amplification, sequencing and computational phylogenetics and to assess alterations in the gut and skin microbiota of patients with moderate to severe rosacea in response to varying formulations of antimicrobial treatment.
233 studies on the registry are indexed under Rosacea; 23 are open to participants now.
This study's planned enrollment of 150 is above the median of 61 across 200 interventional studies indexed under Rosacea.
Browse Rosacea studies →Johns Hopkins University is the lead sponsor of 1,815 studies on the registry; 315 are open to participants now.
Of its 208 completed or terminated interventional studies of FDA-regulated products, 144 (69%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Doxycycline 40mg will be administered once a day per oral for 28 days.
Drug: Doxycycline
Doxycycline 50mg will be administered once a day per oral for 28 days.
Drug: Doxycycline
Doxycycline 100mg will be administered once a day per oral for 28 days.
Drug: Doxycycline
Doxycycline 100mg will be administered twice a day per oral for 28 days.
Drug: Doxycycline
Topical ivermectin will be applied once a day for 28 days.
Drug: Ivermectin Topical
No intervention will be performed.
The investigators will administer doxycycline to rosacea patients according to the dose of patients' assigned study arm.
1% topical ivermectin.
Difference in skin and gut microbiome between rosacea and control
Differences between microbe communities in patients with rosacea and controls without rosacea will be assessed using a 16S rRNA PCR amplification, sequencing and computational phylogenetics.
Time frame: 2 months
Change in skin and gut microbiome after 4-week of antimicrobial treatment in rosacea patients
Alterations in the gut and skin microbiota of patients with rosacea in response to varying formulations of antimicrobial treatment will be assessed.
Time frame: Baseline, 28 days
This study is active, not recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Doxycycline