Microvascular Pattern and Blood Stasis in Skin Disease

Abstract

Some of the factors contributing to severe intravascular stasis in the blood vessels supplying the epidermis are discussed. Changes in blood viscosity result from a variety of factors which act maximally at the peak and in the venous arm of the papillary vessel. The influence of cold on blood viscosity in the papillary vessel is particularly emphasized.The importance of aggregation of blood cells in the superficial vessels and of factors such as platelet aggregation, which may be irreversible and may influence disaggregation are discussed.The presence of *' preferential channels ' * in the capillary meshwork of the skin is illustrated and their significance as passages permitting redistribution of blood away from the epidermis is emphasized.Studies of platelet stickiness in a group of patients suffering from sensitivity to cold and studies on blood flow in one patient with acrocyanosis are presented.CESSATION of blood flow in the superficial microvascular sj'stem for a period sufficiently lorvp; to cause ischaeniic necrosis of the epidermis is rare, but it may occur when there is a summation of several factors tending to increase the viscosity of blood or to encourage intravascnlar clotting. Severe intravascular stasis in the cax^illary loops snx^plying the epidermis may be seen in a number of diseases inclnding severe chilblains, scleroderma, rlieumatoid arthritis, lujius erythematosus, dermatomyositis, acroeyanosis, and many of the dermatological diseases often classified nnder the headino; of " vascnlitis ". There is increasing knowledge al:»out the factors that oneouragc stasis and an interest in mechanisms such as disturbances in tibrinoiytic activity is apparent in dermatological literature (Hatano el al.. 1902; Hatano and Y^aniamoto, 1963; CunlifFe, 1968; Brodthagen et al., 196S and Haustein, 1968).It is the object of this paper to emphasize some of the factors, such as cold, that encourage stasis and to show how the microvascular pattern of the skin can determine the nature ofthe pathology which results from stasis.The patterns of tho microvascular system ofthe skin vary in normal as well as in diseased skin, but tbe commonest pattern of supply to tbe epidermis is ilinstrated in Fig. I. The capillaries that provide nourishment for tbe e])iderniis are loops Avhich arise from a candelabra-like pattern of arterial vessels and tlieir contents di-ain into a venous system which, in ti^e upper dermis, is horizontally disposedthe snbpapillary venous plexus. Tbe greatest density of the vascular system is at the most snperfieial level and thus large quantities of blood are exposed to the temperature of the external environment.

Surgical Treatment of Livedo Vasculitis

“…According to the literature, no single or combined form of therapy has been effective for the treatment of atrophie blanche. Anticoagulants, 14 anti‐inflammatory agents, dextran infusions, and topical or systemic steroids have not been helpful. Sympathectomy has been tried without success 7 .…”

Microbial Factors in Psoriasis

“…While the anti¬ gen portion of those complexes has not been identified, products of Gram-negative bacteria represent a reason¬ able possibility. 9. Presence of proteases.…”

Traitement de la vasculite livédoïde par des perfusions d’un hydrolysat de dextran à 10%

“…Les traitements proposés jusqu'ici pour cette affection se sont révélés décevants, qu'il s'agisse de sympathectomie [1-3, 9, 10, 16], de ligature de la saphène [16], de l'ad ministration de sulfamidés ou d'antibiotiques tels que les tétracyclines ou la pénicilline [16], de griséofulvine [16], d'antimitotiques tels que le méthotrexate [16], d'antihistamini ques à haute doses [16], de rutinc [14], de collagénan [14], de réserpine [14], de corticostéroïdes [1,16], d'hexaméthonium [9,16] ou de guanéthidine [16]; peut-être l'acide nicotinique [16], l'association phenformin-éthylestrenol [4,[6][7][8]II,13] ou les anticoagulants [5,12,[14][15][16] ont-ils donné quelques résultats favorables. Ryan et al [15] ont, en outre, mentionné sans détails que les dextrans de faible poids moléculaire pouvaient être utiles.…”

“…Ryan et al [15] ont, en outre, mentionné sans détails que les dextrans de faible poids moléculaire pouvaient être utiles.…”