Scientists hunt for hidden causes of painful leg ulcers in sickle cell disease

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA: We will enroll up to four-hundred and fifty (N=450) participants in the microbiome sampling cohort. In addition to the 300 SCD leg ulcer microbiome participants, we will recruit up to an additional 200-250 SCD participants that will complete the clinical evaluation, (including blood sample) and survey instruments for a total of up to 550 participants at three sites, NIH (n=200) and MMC (n=100), and Sierra Leone (n=250). Of the total participants, we will resample the microbiome of up to 75 individuals from each of the 3 initial sampling groups: SCD with, without and never had SCD leg ulcers. Of those 75 individuals who are sampled longitudinally, those with clinically interesting cases may be sampled at multiple intervals. All sampling, surveys, and processing of samples will take place at the NIH Clinical Center the second site, MMC, or in Sierra Leone. All samples will be stored at NIH. To be eligible to participate in this study, an individual must meet all of the following criteria: * All subjects must have a diagnosis of sickle cell disease (HbSS, HgSC, HbSB 0 or HBSB+) * Be at least 18 years old. * Provide written informed consent. * For the Qualitative phase: must have a recurrent, active, or single-occurrence presentation of a leg ulcer(s). * For the resilience study analysis: cohort will be determined by the research team based on the results of part I of this analysis. For part I, the inclusion criteria are that the individual must have enrolled and completed the INSIGHTS study. EXCLUSION CRITERIA: Any individual that meets any of the following criteria during baseline evaluation will be excluded from the study: * Pediatric population (\<18 years old) * Participants for microbiome study (only) who have received oral and/or topical antibiotics or antifungals \< 2 weeks prior to enrolling in the study for leg ulcers (for those with leg ulcers only) * Subjects presenting with clinically diagnosed bacterial infection (i.e. clinical appearance, clinical judgment, fever, redness around ulcer, purulent drainage etc.) at the site of ulceration. (This can only be diagnosed clinically by the research nurse during sampling and is only applicable to those with leg ulcers only).