My take is that you don't (in the resume).
You tailor your experience with the job description at hand. With healthcare, you have different fields and specialties. Without knowing what exactly you are applying to, it would be difficult to ascertain what to do exactly.
Look for keywords in the job description, does it say "Provide Care to Patients"? Then perhaps a retail-equivalent would be "resolve customer complaints". The first asks for people-skills, the second states that you have people skills.
Although the lines connecting the Job at hand and your Experience are not very exact, it will be something to springboard off of in your applications. Now in your cover letter you can then go on to explain the circumstances surrounding your choice of employment these past few years. "Take care of family, I found employment in a number of part time retail roles... but now I am back on track and want to pursue a career in Healthcare X".
If the role doesn't allow for a cover letter, try to reach out directly to the hiring manager or main point of contact and ask if you can submit one. My bet is that smaller agencies/companies/clinics would be more receptive and attentive to individual applications versus large agencies/companies/hospitals.
Best of luck.