Definition. A common, functional, sensory neurosis of the skin, characterized by some variation of itching without a primary cutaneous alteration.
Symptoms. In reality pruritus is a form of paresthesia and may be differentiated from itching that is symptomatic of some skin disease because it stands here for a disease entity apart from any cutaneous lesion and not for a symptom alone, although scratching may cause an eruption varying from a mild dermatitis to a true eczema. The degree of itching may be so slight that there is scarcely any inconvenience, or it may be increased in other cases to a degree that causes severe mental disorder. It is often localized and may rarely be general (pruritus universalis). It may be constant, intermittent or remittent without any order as to its appearance, is often aggravated by changes in temperature, by bathing, and is invariably worse at night. Pruritus senilis is a persistent, distressing and often incurable general form of this disease due to atrophy and other senile changes in the skin. It is, however, often related to diabetes and kindred affections.
Pruritus hiemalis (frost itch, winter itch) occurs only in the cold season. It is usually noted upon the non-hairy surfaces such as the lower part of the legs but occasionally the arms and other parts are involved. Often it is not noticeable during the day but, on removing the clothing at bedtime, it is very pronounced. It may persist throughout the winter, only disappearing in the late spring, or it may be more or less intermittent. Occasionally prurigo-like papules have been found on the parts affected or a real eczematous condition may result from scratching. Adults are those most affected while a similar condition (pruritus aestivitis), occurring in the warm seasons and not related to miliaria, may affect people of any age. Pruritus following a bath (bath pruritus) may be more or less general. The attack will last for a few minutes to as many hours and the degree of itching may be of any intensity. Young adults with a naturally dry skin are those usually affected.
It is not unusual to find pruritus limited as regards the area involved. Thus the palms and soles (pruritus palmae et plantae) may be involved, coexisting with hyperidrosis, gout, malaria, or asthma. Pruritus is not uncommon on the face, back of the neck, the angle of the nose and mouth, and occasionally the scalp. When the Schneiderian membrane of the nose (pruritus narium) is involved, there is usually present a rose or hay asthma, although the condition may follow the use of opium and its alkaloids and has occurred in children from parasitic irritation, Pruritus genitalia is not uncommon, although it may exist in a mild form and the sufferer will not seek treatment until secondary eczematous changes have developed. In men the commonest location is the scrotum (pruritus scroti), perineum, anus and urethral orifice of the penis. Pruritus vulvae may affect all the external female parts, extend into the vagina or become extragenital. This form is most demoralizing, often intolerable in its itching and may lead to obnoxious practices. Some severe cases have been traced to glycosuria, uterine or ovarian diseases. Pruritus ani is very common in both sexes and, although usually found in adults, may exist at any age. It is a primary or secondary neurosis associated with such changes as hemorrhoids, hyperidrosis, constipation, fissures, eczematous or other irritations. The orifices often present a sodden appearance and there is usually a foul-smelling secretion.
Etiology and Pathology. Causes which underlie sensory disturbances may be congenital or acquired, local or general. Many general conditions act as predisposing causes of pruritus but by far the most essential and ever-present is hyperaesthesia. Generalized itching may be caused by mental or physical neuroses, hysteria, neurasthenia, rheumatic, catarrhal or gouty diatheses, kidney, liver, genitourinary, uterine, ovarian, gastric or intestinal disorders, pregnancy, excessive and long-continued use of alcoholics, tobacco, coffee, tea, opium and its alkaloids, and excessive heat and cold. I believe that gastrointestinal disorders are usually present in some degree with many of the causal elements mentioned above but, in some cases, these distinctions properly belong to the nerve specialist and not to the dermatologist. Pruritus hiemalis is essentially due to the cold weather, although the wearing of rough underwear together with a gouty or rheumatic tendency and a defective digestion lend a helping hand. Water is the active cause of bath pruritus but those involved have a harsh, dry and easily irritated skin. The local causes present in pruritus ani are hemorrhoids and other rectal complaints, intestinal worms, constipation, lithemia and the like. The habit of scratching due to eczema, pediculosis or other itching diseases may remain after the actual diseases have disappeared and constitutes a pruritic habit. While pruritus vulvae is often due to diabetes, it may result from worms, pregnancy, uterine or ovarian diseases, or from leucorrheal or more specific discharges. Pruritus scroti has been caused by urethral malformations or bladder disorders and is common to those who sit with crossed legs like tailors. Naturally the causes which produce a symptomatic itching of the skin in other eruptive diseases, especially in the animal parasitic affections, are excluded here although they should be always borne in mind in searching for the cause of true pruritus. It is necessary to call some cases idiopathic because different search fails to yield an apparent cause.
Pathologically this condition is a sensory neurosis due to irritation involving the nerve supply of a part at some point between the central origin and distal terminations. The tissues are found unaltered except as far as secondary changes may influence them.
Diagnosis. Itching being the one diagnostic symptom, it is only necessary to exclude other pruritic affections of the skin to establish a diagnosis. The absence of eruptions, except excoriations from scratching, makes this usually easy. Eczema may be secondary to an essential pruritus and obscure the nature of the primary disturbance. The history of origin will generally clear away this doubt. Parasites should not be forgotten as possible factors even in unusual locations and at times on the cleanly. For a differentiation of pruritus from prurigo, see the latter.
Prognosis depends upon the discovery and removal of the cause. Pruritus hiemalis is apt to recur the next season and the chances for a permanent cure in pruritus senilis are poor.
Treatment. All possible etiological factors must be taken into consideration in the treatment of this diseases because no amount of local treatment is more than palliative. Naturally the lines laid down for the treatment of the underlying diseases are those to be pursued in the main. It is quite unnecessary in a book on dermatology to outline the detailed management of any of the systemic or local conditions mentioned under etiology as causative. Examination of the urine, feces and blood should be made if there is the slightest advantage to be gained therefrom and none of the viscera should be neglected in this respect. Sedatives and narcotics, especially opium, should be discouraged except in extreme cases. Woollen and other irritating underclothing should be avoided at all times. Diet is always an essential item in the general treatment and should be plain while nourishing, always avoiding stimulants, rich foods, excessive amounts of starches or heavy materials, shell fish and all varieties of preserved, salted or dried foods. Water between meals is usually essential and saline laxatives are often indicated. The galvanic current, high frequency currents or the static roler electrode applied to the spine may give relief if the pruritus is of general extent.
External treatment is demanded as a measure of relief and the means employed are as numerous and varied as the imaginations of those employing them. It is my purpose here to speak only of those agents that personal experience has proven to be useful. The high-frequency currents are often useful in localized forms of pruritus, especially in the anogenital regions. The same may be said of the X- rays but I prefer them for localized pruritus of other regions, because of the danger of producing sterility when used in the genital regions. Of course, this does not apply in the case of older people where the matter is of no importance. In a few instances when other means have failed, radium has afforded comparative relief for four or five days, the applications varying from fifteen to forty- five minutes. Complete recovery occurred from radium in two of my cases of pruritus vulvae, one after six treatments and the other after eight. I mention these forms of physical therapeutics first because I consider them superior to any but the simplest forms of the older local treatments. Local applications of very hot or very cold water, alcohol, bicarbonate or biborate of soda solution, hydrogen peroxide, or adrenalin chlorid (1:1000) well diluted, may afford comfort and will not interfere with internal treatment. If pathogenetic antipruritic, agents are to be used, ointments are often preferable, due to the dry condition of the skin although there is no hard and fast rule as to this. Lotions are cleaner and preferable in generalized itching. Carbolic acid is more often applied than any other agent in the form of a 1 to 5 per cent. lotion, or 5 to 20 per cent. in oil or ointment. Orthoform, iodoform, thigenol, calamine, ichthyol, resorcin, thymol, menthol, camphor and liquor carbons detergents may be used in lotion or ointment as the following prescriptions will show:
American homeopath, he directed several hospitals in New York.
Professor of dermatology.
Served as Lieut. Colonel during the 1st World War.
See his book online: American homeopathy in the world war