Your sharpie would be having either allergic or irritant contac dermatitis
Or it would be some chronic relapsing disease like lichen planus
For actual diagnosis, he should consult to dermatologist
After complete diagnosis, proper treatment may be given.
Local steroids with antibiotic cream may be encountered.
Oral steroids in tappering dose may be helpful.
Avoidance of contact with dust, soap, grass..etc may be helpful.
I hope you got my answer.
Dr. Ilyas Patel MD