Skin is the largest organ in the body. The skin protects us from ultraviolet light, chemical and infective organisms in the atmosphere. And regulates body temperature, gathers sensory inputs from the environment, stores water, fat, and vitamin D, and plays an important role in our immune system, protecting us from the disease.
Ayurveda explains twak as one among the 5 gyanendriya, attributed with the function of sensation of touch and is the location (ashray sthana) of sweat channels (swedavaha strotas) and hairs (loma).
According to Ayurveda there are three elements in the body: vata, pitta and kapha which affect the body functions when imbalanced. In skin diseases, all the three Doshas (Vata, Pitta, Kapha) are involved either solely or in combination vitiating them to the tissues (Dhatus) level; Rasa (plasma), Rakta (blood), Lasika (lymph) and Mamsa (muscle). As the disease progresses more tissues (Dhatus) may get involved.