Your private medical history, disabilities or health issues are just that: private. As long as you are physically capable of performing the job you are applying for, you should not bring up disabilities or health issues on your resume or cover letter.
You can usually judge your physical capability by reading the job application or posting. Does the job require lifting a certain weight, flying or driving regularly, or climbing a certain distance? If you are not able to perform functions that are clearly required by the job, then your employee has every right to know that. In fact, if you cannot perform the functions of a job, you should probably change your job search.
I have worked with clients who have obvious disabilities and have helped them to find a job that not only matches their abilities but furthers their careers.
For example, I worked with a deaf computer programmer who had held a series of jobs in which he had to interact verbally with a team. Unfortunately, he had not been successful in keeping the jobs. In corresponding with him, I found out that he had volunteered for an organization to make their webpages disability compliant. I encouraged him to apply for jobs using his knowledge of what was required to make websites disability compliant, jobs which celebrated his skills. He became excited about this opportunity. Using this new focus, I created a resume which he used to successfully obtain his next position.
The Americans with Disabilities Act (ADA) does not require job applicants to reveal a disability on a resume. If the disability will be obvious in an interview, try to get the interview first. That is the time when you can prove to an employer that you are differently abled, not disabled, and that your different abilities will not interfere with your performance and productivity.
Employees are required to accommodate disabilities in the workplace; it pays for you to research what accommodations you would need and to have sources and costs ready to quote at the interview. The average cost for an accommodation is about $500—and it could be zero if the employer already has technology and other resources in place.
According to the U.S. Department of Labor Bureau of Labor Statistics, 17.5% of people with disabilities were employed in 2015. This is still well below the figure for people without disabilities. The largest portion of people with disabilities work in manufacturing, education and health services, then finances and retail.
Illnesses that require frequent absences for doctor appointments or treatments should be discussed with the employer, just as the need for any other accommodation. But again, this information does not belong on a resume or cover level. In fact, the ADA does not require you to reveal an illness at any specific time; you can wait until the interview, until you require accommodation or until you are ready.
Please contact me if you need help with your resume or career focus. I can help write a resume that is honest and that will also give you the best opportunity for that first interview.