Perniosis

PERNIOSIS (perniosis, perniones, erythema pernio), a group of skin changes caused by cold. They must be distinguished from frostbite for the following reasons: 1) in contrast to frostbite, P. most often occur at temperatures above 0°; 2) a special predisposition is required for their occurrence; 3) they are characterized by a peculiar clinical picture, localization, and a persistent tendency to recur. Closely related to P. is erythrocyanosis crurum puellaris (see Erythrocyanosis cutis-symmetrica) and cutis marmorata (see Livedo). Etiology and pathogenesis. The main etiological factor is cold, especially in combination with dampness and sharp fluctuations in temperature. These circumstances are often closely linked to the patient's profession (vendors in food kiosks, cleaners, etc.) and give P. the character of a professional disease. P. most often occurs in autumn and spring. The development of P. requires a certain individual predisposition. Women are affected more often than men. Children and adolescents are most frequently affected. Sometimes patients are found to have a deficiency of endocrine gland function, nervous disorders, chlorosis, heart diseases, etc. Some authors attribute a pathogenic and even etiological significance to tuberculosis, since sometimes tuberculinids develop on the chilled areas; according to other authors, cutaneous tuberculosis develops secondarily in the areas of perniosis due to the reduced resistance of the tissues. Some light is shed on the nature of the predisposition to P. by histological and capillaroscopic studies. In P., the action of cold is manifested first in the area of hair follicles (edema, infiltration) and on capillaries (ectasia, thickening of the walls, thrombosis). These initial changes, progressing further, give pictures that do not differ fundamentally from frostbite. Capillaroscopy in P. shows capillary aneurysms, as well as dilation of deeper vessels and on healthy areas of the skin. Thus, the essence of the predisposition to P. is reduced to functional insufficiency and reduced resistance of small vessels and capillaries. Symptoms and course. Clinically, one can distinguish diffuse erythematous (erythema pernio) and limited nodular (perniones) forms of perniosis, which are usually combined. Hyperhidrosis of the hands and feet often accompanies them. In its pure form, erythema pernio occurs almost exclusively in women in the area of the shins, knees, buttocks, and extensor surfaces of the hands. The color of the skin of the affected areas varies from bright red to cyanotic and is sometimes uniform, sometimes spotted and reticular. Lichen pilaris (perniosis follicularis) is often observed. The nodular form of P. develops against the background of erythema. The most frequent localization is the fingers of the hands and feet, especially their dorsum. Less often, P. occurs on the nose, ears, and cheeks. The skin first swells, becomes edematous and cold to the touch, and has a cyanotic-red color. Then, diffuse, juicy nodes of violet-burgundy color form, easier to determine by touch than by sight. In the future, cracks or blisters may form, followed by sometimes quite deep ulcers. The nodes are often accompanied by severe itching and burning. The course of both forms is protracted and persistent. In warm weather, P. passes, but with the onset of autumn they recur. Diagnosis of P. is not difficult; it can be confused with erythema induratum Bazin and lupus pernio. Treatment should be directed at strengthening the organism when required and at raising vascular tone in the affected areas; for this, alternating cold and hot local baths, rubbing with camphor alcohol, iodine applications, etc., are recommended. Irradiation with ultraviolet rays and also roentgenotherapy are also beneficial. For cracks and ulcers, antiseptic ointments (xeroform, Peruvian balsam) are used. Prophylactically, it is important to protect the affected areas from cold, dampness, and sharp fluctuations in temperature before the onset of autumn. Anything that can impede peripheral circulation (bandages, tight sleeves and cuffs, etc.) must be eliminated. In professional selection, the tendency to P. and the nature of the proposed work must be taken into account.

S. Rozenthal. 030 Combustion is produced by burning organic matter and is used for the qualitative and quantitative determination of its mineral components or mineral impurities. For an approximate test, a small amount of the test substance is burned beforehand on a platinum plate. For the purposes of a complete analysis, a larger amount of the substance dried to constant weight is burned in a platinum crucible, heating it first on a small flame, and then to the beginning of red heat. Heating is completed when the last traces of coal have disappeared in the ash residue. If this does not happen for a long time, a few drops of a saturated solution of ammonium nitrate are added to the precipitate. Another method of combustion consists in the fact that during the course of combustion the charred substance is several times extracted with water with careful stirring and filtered through ashless filters; the latter are burned with the precipitate. The combined filtrates are evaporated. The advantage of the first method is greater simplicity, the second is the elimination of the volatilization of alkali metal salts, the possibility of reducing sulfuric and phosphoric acids, and greater speed of combustion. If the test substance contains chlorine, phosphorus, or sulfur, which give volatile oxides, the substance is mixed with soda or with calcium, magnesium, and other salts before combustion. In addition to the above dry methods of combustion, there are also wet methods, when the substance is burned by heating it with a mixture of equal volumes of concentrated sulfuric and nitric acids. The ash residue of small amounts of organic matter can be obtained by micro-combustion in a small platinum crucible.