A dermatologist is a doctor who has extensive training and knowledge of the skin, scalp, hair and nails and treats conditions that affect those areas. These doctors will evaluate any abnormality, blemish or lesion on the skin in order to determine the cause and will determine a course of treatment.Dermatologists provide patients with full body scans in order to identify any signs that are indicative of an illness that requires treatment, such as skin cancer. These specialists may also provide cosmetic services, such as mole removal, scar diminishing treatments and even botox and face lifts.

A gastroenterologist is a specialist in diagnosis and treatment of conditions involving the digestive/gastrointestinal (GI) tract. These doctors are experts on how food moves through the digestive system and is chemically broken down, with nutrients being absorbed and waste excreted. You might see this kind of doctor if you are experiencing any number of stomach issues, some of which might be severe diarrhea, irritable bowel syndrome, hemorrhoids, ulcers, acid reflux, Crohn's disease and more.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.