The skin and subjacent tissues, including the periosteum, from being simply swelled or œdematous may become thickened and hypertrophied. The writer has known a case of supraorbital neuralgia, at first typically intermittent, to lead to a thickening of the periosteum or bone over the orbit, which even at the end of several years had not wholly disappeared.
Neuralgias of the fifth pair, which are as remarkable in their outward results as they are in their severity and their relation to other neuroses, are said to give rise to clouding and ulceration of the cornea, to iritis, and even to glaucoma.
Herpetic eruptions on the skin sometimes occur, of which herpes zoster is the most familiar instance.
Muscular atrophy is very common, especially in sciatica, and in some cases this occurs early and goes on rapidly, while in others it may be only slight and proportioned to the disease and relaxation of the muscles, even where the neuralgia has lasted for weeks or months.
Neuritis of the affected nerve is a common result or attendant of neuralgia, and may remain behind for an indefinite period after the acute pain has gone, manifesting itself by subjective and objective disorders of sensibility, by occasional eruptions on the skin, or by muscular atrophy.
It is plain that in this list of symptoms a variety of conditions have been described which would never all be met with in the same case, and which, as will be shown in the section on Pathology, are probably due to different pathological causes.
Neuralgia of the Viscera.
These neuralgias are less definitely localized by the sensations of the patient than those of the superficial nerves, and it is not definitely known what set of nerves are at fault.
They are deep-seated and are referred to the general neighborhood of the larynx, œsophagus, heart, or one of the abdominal or genital organs, as the case may be.