A Phase 2 interventional study of Trimethoprim/sulfamethoxazole (TMP/SMZ) and Cephalexin in Eczema, Dermatitis and Skin Diseases, Genetic, sponsored by National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Recruiting at 1 site in United States. Open to participants aged 2 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) · Phase 2, Interventional, and Treatment
Background:
- Atopic dermatitis, or eczema, is a chronic skin disorder. Patients sometimes have infections with S. aureus bacteria. Researchers want to study how eczema treatments affect the number and the type of bacteria on the skin.
Objectives:
- To study the effect of eczema treatments on skin bacteria.
Eligibility:
Design:
BACKGROUND:
OBJECTIVES:
Primary:
- To characterize microbiome alterations in healthy adult volunteers and patients with AD after antimicrobial treatments.
ELIGIBILITY:
DESIGN:
503 studies on the registry are indexed under Eczema; 89 are open to participants now.
This study's planned enrollment of 130 is above the median of 91 across 401 interventional studies indexed under Eczema.
Browse Eczema studies →National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) is the lead sponsor of 100 studies on the registry; 12 are open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 5 (71%) have results posted.
Counted across the registry records on this site, refreshed daily.
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.
Cohorts 1 [NO FURTHER ACCRUAL], 2 [INACTIVE], 4 [NO FURTHER ACCRUAL] and 5 [INACTIVE]: Healthy Volunteers
Cohort 3 [INACTIVE]: Atopic Dermatitis Patients
the procedures of the protocol and provide informed consent. Pediatric patients will be included in age appropriate discussions and
age appropriate assent will be obtained in accordance with NIH guidelines.
-Ability of subject to understand and provide written informed consent
Cohort 6: Healthy Volunteers
EXCLUSION CRITERIA:
Cohorts 1 [NO FURTHER ACCRUAL] and 2 [INACTIVE]: Healthy Volunteers
Cohort 3 [INACTIVE]: Atopic Dermatitis Patients
Cohorts 4 [NO FURTHER ACCRUAL] and 5 [INACTIVE]: Healthy Volunteers
Cohort 6: Healthy Volunteers
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.
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.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
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.
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
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.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cephalexin + Placebo bleach
Drug: Cephalexin
TMP/SMZ DS 800 /160 orally every 12 hours for 14 days
Drug: Trimethoprim/sulfamethoxazole (TMP/SMZ)
Doxycycline 100 mg orally every 12 hours for 56 days
Drug: Cephalexin · Other: Sodium hypochlorite
Doxycycline 20 mg orally every 12 hours for 56 days
Drug: Doxycycline
Systemic antibiotics (Cephalexin) + dilute bleach study bath liquid
Drug: Cephalexin · Other: Sodium hypochlorite
Systemic antibiotics (Cephalexin) + placebo study bath liquid
Drug: Cephalexin · Other: Placebo Sodium hypochlorite
Placebo capsules + dilute bleach study bath liquid
Other: Sodium hypochlorite · Other: Placebo capsules
Placebo capsules + placebo study bath liquid
Other: Placebo capsules · Other: Placebo Sodium hypochlorite
Systemic antibiotics (Cephalexin) + dilute bleach study bath liquid
Drug: Cephalexin · Other: Sodium hypochlorite
Systemic antibiotics (Cephalexin) + placebo study bath liquid
Drug: Cephalexin · Other: Placebo Sodium hypochlorite
800/160 orally every 12 hours for 14 days
500 mg orally every 8 hours for 14 days
20 mg orally every 12 hours for 56 days or 100 mg orally every 12 hours for 56 days
6 % dilute bleach
Capsule orally every 8 hours daily for 14 days
Three times a week for 14 days
Characterize microbiome alterations
Difference in Shannon Diversity Indices (SDI) from baseline to day 14.
Time frame: 2 weeks
To obtain samples from healthy adult volunteers to evaluate and refine genomic analysis of human microbes.
Time frame: Throughout the duration of the study
To examine how different antimicrobials may alter the human microbiome.
Time frame: Throughout the duration of the study
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Doxycycline
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) →