Below are some of the specialties with the highest salaries. Dermatology. According to a survey conducted by the Medical Group Management Association in 2013, the average salary for a dermatology physician assistant was $130,000 a year.urgery. Surgery is often a high paying specialty for doctors and the same holds true for physician assistants. The average salary of a surgical physician assistant in 2013 was $115,000 a year according to the United States Bureau of Labor Statistics.