(Malum perforans pedis)
This rare trophoneurotic disease begins with the formation of a localized callosity or corn, first developed upon an exposed location such as the plantar aspect of the metatarsophalangeal joint of the first or fifth toes, although it has been noted on the palm of the hand. Beneath the corn a sinus develops which ulcerates its way slowly inward until it involves soft parts and bones. The external opening is by the side of the original corn and is sometimes surrounded with granulations; usually it is a small opening but later, by continued pressure in walking, the epidermis becomes thickened into a large whitish-yellow mass which surrounds the orifice. With these changes occur other trophoneurotic manifestations, such as thickened epidermis, altered nails and excessive hair growth on the extremity and dorsum of the foot. Pigmentation of variable degree, erythema or eczema, increased or diminished sweating, anesthesia in and around the ulcer and neuralgic and rheumatic pains in the affected extremity may also be present.
Etiology and pathology. – When a nerve supply is interfered with, as may occur in locomotor ataxia, anesthetic leprosy, spinal injuries, syphilis, neuritis, diabetes, etc., this rare condition may ensue. It is conceded that this malady is a trophoneurosis depending upon the impairment or degeneration of peripheral, truncal or central nerves.
Diagnosis. – It would not seem that mycetoma, callositas, suppurating corns, or tuberculosis cutis should be confused with this condition, if its general nervous phenomena be considered.
Prognosis and Treatment. – The former is doubtful and treatment unsatisfactory. Curetting, excision, partial or complete amputation or simpler measures afford only temporary relief because the condition is apt to recur even in the stump of the amputated part. In a case case of my own. Arsenicum alb. and Populus cand. were well indicated and apparently gave relief.