The skin is the largest organ in the body. Elastic, Waterproof, Light proof, and self mending.
it renews it self constantly and adapts to fit us perfectly from childhood and adulthood to venerble old age.
     Ayurveda classifies skin disease into two based on the involvement of dossiers and pathological process of disease - 
VISARPA - Visarpa is a pitta disease in which due to excessive in crease of pitta (fire) in Rakta Dhatn assumption and boils paper on the skin, these quickly spreading and become ulcer.
TREATMENT- Purification by virechana and Rakta mokshana Snehana and use of ghee preparation are C.I in the early stages of Visarpa as there is too much Ama ( Toxins )in the disease.
       After internal purification, ext. applications of medical paste and oils are useful in Visarpa. 
Aviepathy Choorna, Mahatiktam Kashaya can be useful for int. purification. herbs like Neem , Turmeric can be useful as well.
KUSHTA - The word Kustha means to putrefy or decay Dhatne - skin, mama ( flesh ) Become putrefied and decayed in this disease due to excessive formation of Kleda ( Fluid Waste)in the body. it is a chronic disease and takes a long time to spread.
TREATMENT - Strong Purificatory treatment - Vamana Virechana and Shirovirechana are recommended. 
some of the medicines useful in Kustha are Manibadsam lehyam, Argwadhadi Kashaya, Patolamooladi Kashaya and herbs like Khadisa , Manjeestha , Sariwa , Gnduczi are the best.