This condition may be described as an exaggerated sensitiveness caused by external factors, as contrasted with the spontaneous origin of paresthesia and dermatalgia. It may be general or local, unilateral or symmetrical, the distribution giving a clue to the affected nerves. Every contact with the skin gives an exaggerated impression to the central organs. It is frequently noted in hysteria, in which disease it is inconstant in location and duration. Most cases are symptomatic of functional or organic diseases of the central or peripheral nerve systems but a few are idiopathic or at least no cause is apparent. It may be here remarked that the line of demarcation between paresthesia and hyperaesthesia is very finely drawn and the conditions are often difficult to differentiate.
Prognosis and Treatment depend upon the underlying nervous condition causing the hyperaesthesia. Kalmia and Hypericum apparently cured two of my own cases.