Evaluation of a voice disorder usually proceeds by steps – a person pursues more specialized care the more stubborn and resistant to treatment a problem is. For hoarseness that comes with a cold or flu, it is perfectly appropriate to see a primary-care physician. Most such cases resolve with treatment of the underlying illness. Hoarseness that lasts more than two or three weeks should be evaluated by a physician trained to examine the vocal folds and larynx, namely, an otolaryngologist (ear, nose and throat doctor).
The next degree of specialization is that of a laryngologist. Laryngology, the field of medicine that concerns itself with voice disorders, is a subspecialty of ear, nose and throat medicine. Whether or not a voice problem requires the expertise of a laryngologist depends on its nature, and the degree to which a given otolaryngologist feels comfortable handling the disorder.
There is no examination or test that certifies a laryngologist. Initially, otolaryngologists developed a specialization in voice disorders through interest and experience. Nowadays, physicians pursue a course of additional study following completion of their training in general otolaryngology, called a fellowship, devoted to voice and laryngeal disorders. Fellowship training is a good sign that your otolaryngologist has an expertise in voice disorders. Memberships in appropriate professional societies like the American Laryngological Association, and publications in medical journals and textbooks dealing with voice disorders, are also helpful signs.
At minimum, then, the physician evaluating your voice problem should be a board-certified otolaryngologist. He or she should be comfortable discussing various aspects of your disorder, and explaining the problem and proposed treatments in terms that you understand. Armed with the information presented within this site, you should be in a reasonably good position to judge preliminary advice given to you. Note, though, that there are differences of opinion within the field, so certain physicians may view specific problems somewhat differently than they're presented here.
More information, including a means of searching for an otolaryngologist in your area, is available from the American Academy of Otolaryngology – Head & Neck Surgery.