A doctor who studies and treats skin diseases is called -

• A doctor who studies and treats skin diseases is called - Dermatologist.
Dermatologist
English Meaning: A doctor who studies and treats skin diseases
Bangla Meaning: চর্মরোগবিশেষজ্ঞ; ত্বক্-বিশেষজ্ঞ

অন্য অপশন গুলোর মধ্যে - 
• Oncologist - A doctor who has special training in diagnosing and treating cancer.
• Orthopedics - the branch of medicine that deals with injuries and diseases of the bones or muscles.
• Urologist - ​A doctor or scientist who is a specialist in the urinary system

Source: Oxford Learners Dictionary.