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.

An infectious disease specialist has specialized training in the diagnosis and treatment of contagious diseases.
Infectious diseases, also known as contagious or transmissible diseases, are those that stem from pathogen from a host organism. These infections may spread to other carriers through physical touch, airborne inhalation, bodily fluids or contaminated foods.
Infectious disease specialists identify whether the disease is caused by bacteria, a virus, a fungus or a parasite often through blood tests and then determine what course of treatment, if any, is necessary.

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.

A dermatopathologist is an expert in both dermatology and pathology. They specialize in diseases related to the skin, but where a dermatologist would examine a potentially-cancerous mole by looking at it, a dermatopathologist would examine your skin cells in a lab, more like a pathologist.
Beyond just skin cancer, dermatopathologists also study a wide range of skin conditions, including everything from warts, moles, spider veins and herpes, to dermatitis, rashes, vitiligo and other conditions related to skin discoloration.