Some surgeons recommend that in the early stage the method of inducing passive hyperaemia should have a trial in order to abort the septic inflammation. Hot antiseptic poultices act in a similar manner, but they should be discarded after a short trial if the ordinary signs of severe inflammation fail to subside rapidly.
A free incision under general anaesthesia, Nitrous Oxide or .Ethyl Chloride should be made in the middle line of the finger opposite the seat of maximum tenderness and tension. Where the inflammation has extended beyond the finger a further incision may be necessary, in the case of the thumb and little finger in the wrist, and in the case of the three other fingers in the palm.
The after-treatment consists in free flushing or immersion of the hand and forearm in a vessel of warm antiseptic solution—Boric Acid (satu rated), weak Perchloride of Mercury, or Permanganate of Potassium— and the gentle removal of all sloughs. Afterwards the wound should be dressed with warm Boric Acid compresses.
Whilst in the subcuticular and subcutaneous forms of paronychia it is advisable to keep the hand elevated, in the deep tendinous variety this must be avoided in order to prevent the pus burrowing along the tendons. Owing to the danger of matting of the tendons and stiffening of the joints, passive movements, massage and voluntary exercises of the fingers should be commenced as soon as signs of active inflammation have subsided.
Where ankylosis of a joint or total destruction of its tendon results, there may be no resource left to the surgeon hut to amputate a portion or the whole of the useless finger, but this should never be undertaken till long after the active mischief has disappeared.
Subperiosteal paronychia is to be treated like the thecal by a deep incision, which, however, must be carried down to the bone. As a rule no attempt should be made at the removal of any diseased or dead bone till after the subsidence of all active inflammation.
In the chronic forms of onychia due to injury, tuberculosis, syphilis, etc., where active pyogenic organisms play but a secondary part, the best treatment is to surround the finger with a double layer of lint soaked in Spirit or Boric Acid lotion, and cover this by enveloping it with oiled silk, which should be tied tightly like a Christmas cracker beyond the finger-tip without including the lint, forming a perfectly impervious finger-stall.
After subsidence of any active inflammation, the wet should be changed for a dry dressing such as Boric Acid powder, or powdered Nitrate of Lead. Exuberant granulations which do not yield to these dressings may be cautiously treated by a light application of pure Carbolic Acid or a daily application of Sulphate of Copper or Nitrate of Silver, after which any astringent antiseptic ointment may be used as a dressing.
When the above treatment fails, removal of the nail and dressing of the raw matrix with finely powdered Lead Nitrate should be resorted to. Should the onychia return with the growth of the new nail all the tissues on the dorsal surface of the last phalanx, including the nail and under lying matrix, should be shaved off by a sharp scalpel. Or the new nail may be removed with its matrix or the matrix may be destroyed with strong Carbolic or Nitric Acid or Pernitrate of Mercury solution.
Some cases of mild chronic onychia yield to a number of X-ray expo sures which obviate the necessity for avulsion of the nail and prevent the irregular growth so liable to follow when this has been forcibly removed.
Syphilitic onychia is best treated locally with a weak Perchloride of Mercury lotion, Yellow or Black Wash, or by the application of dry Calomel or an ointment of this latter drug.
The onychia which results from tinea and favus must he treated on the lines laid down in the articles on these ailments.
Tuberculous onychia must be met by removal of the nail, scraping away the tissues down to the bone, and, if this be found to be diseased, it should be amputated in order to arrest the spread of the disease along the medullary canal of the adjoining phalanx.
Lateral onychia is the term applied to inflammation following on in growing toe-nail; its treatment is described under its own heading.