Click here to view next page of this article CallusesFoot and Hand Calluses and other Hyperkeratotic LesionsLesions made of focally thickened keratotic tissue may be caused by abnormal pressure. The body responds by trying to protect itself through the formation of hyperkeratosis, which causes increased pressure and pain when thickened or nucleated enough. Common areas in which this occurs are over bony prominences such as the medical aspect of the head of the first metatarsal (bunion) and the lateral aspect of the fifth metatarsal head (tailor's bunion), over contracted digits (corns), or under prominent, lesser metatarsal head plantarly (Callouses). If there is a contracture of bony prominence that causes increased pressure between the toes, a nucleated hyperkeratotic lesion develops. Evaluation of these lesions should include an assessment of the size, depth color, and relationship to bony prominences or weight-bearing areas. It is common to encounter a deep nucleation over areas that receive a large amount of pressure and shearing force. At times, a thickened lesion will exhibit red, brown, or black discoloration caused by small hemorrhages that are caused by pressure and unyielding callous tissue. This is especially serious in patients with peripheral neuropathy caused by diabetes or other causes because these thick lesions can develop an underlying cleavage plane, break down, and then become infected. It is important to differentiate between mechanically induced hyperkeratoses and lesions caused by other conditions such as viral infections (plantarwarts) or blocked sweat glands (porokeratoses). These other lesions may not present on areas of weight bearing or pressure. Plantar warts caused by the human papilloma virus typically exhibit a discrete border, punctate hemorrhages, and papillomatous projections and may be more painful on lateral compression than on direct palpation. Porokeratoses are deeply nucleated without much surrounding diffuse hyperkeratosis. Treatment of the mechanically induced hyperkeratotic lesions includes sharp debridement of the thickened tissue to relieve pain and alleviate the overlying pressure. Changes in footwear, accommodative padding, or foot orthoses may be effective ways to decrease the rate of reformation of the lesion and, at times. Frequently, however, the patient requires periodic reduction of the lesion. If palliation and accommodative devices do not decrease symptoms adequately or the lesions recur rapidly, referral for surgical correction of the underlying bony abnormality may be indicated. Surgically excising the lesion, however, without addressing the cause of the increased pressure ultimately results in reformation. Treatment of verruca plantaris usually involves the debridement of hyperkeratotic tissue and the use of topical salicylic acid preparations that lyse the tissue until it becomes macerated enough to debride to the base of the wart, which extends no deeper. These agents are available without a prescription, are priced reasonably, and usually have accompanying patient education materials that are easy to read. Other topical agents that have been used with variable results are mono-and dichloroacetic acids, cantharidin (a vesicant), and liquid nitrogen, which also is a vesicant that has poor penetration on the plantar aspect of the foot but may be effective on the dorsal aspect. Bleomycin also has been used as an injectable agent that is deposited in multiple areas of the wart in an attempt to cause an inflammatory reaction and eventual resolution, but this treatment may be painful. |