ONYCHIA AND PARONYCHIA.
Acute inflammation of the tissue of the matrix or soft parts surrounding the nail is of septic origin and is known as onychia, and as whitlow or paronychia when the end of the finger is involved, The treatment of the mild subcuticular or most superficial form consists in the application of an evaporating lotion and elevation of the part. As soon as pus appears this may be let out by the prick of a sharp lancet, small bistoury, or sharp scissors—an operation which requires no form of ansthesia owing to the very superficial position of the small abscess.
In the form of whitlow which is caused by the presence of septic in flammation where the nail is covered by the overlapping fold of skin near its root, the pus collecting under the nail must be evacuated under local ansthesia (Ethyl spray) by excising the fold of overlapping skin and removing when necessary a small portion or the whole of the nail itself. Where the infective material has found its way in by the side of the nail, the resulting pus with a small portion of the side of the nail should be removed and the thickened epidermis and overlapping skin sliced off with a sharp scalpel or scissors.
The ordinary subcutaneous form of paronychia or whitlow starts from a punctured wound in the pulp of the finger and requires active treatment in order to prevent the septic inflammation extending to the tendon sheath or periosteum. The acute pain may be relieved by either cold or hot applications, both of which tend to reduce the high tension which causes the acute suffering. As soon as pus has probablv formed a free incision should be made into the swollen pulp of the finger, when possible, under a general anmsthetic, as the operation is accompanied by intense pain, which withstands freezing or other methods of producing local insensibility.
An important point should not be lost sight of—as long as the par onychia is confined to the pulp the surgeon should avoid opening the sheath of the tendon, otherwise the knife, after passing through the infected tissues, will carry the septic organisms into the synovial membrane and convert a subcutaneous into a theca] felon. Hence a further reason
for inducing complete anaesthesia, under which a more accurate gauge of the depth of the incision can be formed ; moreover, under local anxsthesia the patient is certain to pull his finger away vigorously from the knife, when the tendon itself may be divided or only an incision effected which is too small to provide free drainage.
A valuable guide to the requisite depth of the incision is afforded by examining the power of flexion of the last joint of the affected finger. As long as the patient can freely bend this it may be taken as proof that the paronychia is still subcutaneous and the sheath should not be injured. No curettage is permissible for fear of opening fresh tissue to infection.
The best procedure after incision is to place the hand with its freely incised finger in a deep basin of very warm antiseptic liquid, in which it may be kept for several hours if the pain is severe, after which compresses of warm saturated Boric Acid solution may be applied under oiled silk fur several days, when dry dressings or Boric Ointment may be applied to relieve the sodden condition of the superficial tissues and to hasten the healing process. Any exuberant granulations springing from the wound during healing may he rubbed with a large crystal of Sulphate of Copper or touched with a piece of matchwood dipped in Carbolic Acid, but this latter substance should only be applied by the surgeon himself owing to the danger of producing gangrene when too freely applied.
The treatment of tendinous whitlow should be prompt; it is a mistake to wait for evidence of pus formation, as the greatly increased tension caused by the inflammatory process is fatal to the integrity of the parts, and is liable to lead to destruction of the flexor tendon and a useless finger, or the mischief may extend to the bone and cause necrosis, or it may extend up the arm as a dangerous cellulitis.