Anesthesia of the skin may be partial or complete, of central or peripheral origin, with or without structural changes in the skin and may involve one or all of the elements of cutaneous sensation. The sense of feeling may be entirely lost or the sense of touch impaired, there may be a loss of sensitiveness to pain without the impairment to the tactile sensation, or there may be actual pain in the part with a loss of contact or ordinary sensation (analgesia dolorosa of Romberg). In origins this condition may be idiopathic or symptomatic and due to internal or external causes. Among the external agents are traumatisms, cold and the application of ice, ethyl chlorid, cocain, adrenalin, chloroform, etc. Internal anesthetics such as chloroform, ether, nitrous oxid, etc., need no mention here. This condition has been noted in such diseases as syphilis, leprosy, scleroderma and hysteria and has been associated with definite lesions of the nervous system, brain and cord.
Prognosis and Treatment. These depend entirely upon the underlying condition and the neurologist is often more properly consulted than the dermatologist. I have used with success Popules cand. and Secale.