Paediatric haematohidrosis: an overview of a rare but clinically distinct condition.

Haematohidrosis is a rare and dramatic condition in which bleeding occurs spontaneously from intact skin. We report the case of a nine-year-old boy with a typical clinical presentation. The case highlights how challenging it can be for medical professionals to recognise and evaluate rare conditions. A review of the literature was performed, showing that haematohidrosis is mainly a paediatric condition. Our case together with findings from the review indicates that treatment with Beta blockers may be effective for treatment of haematohidrosis in children. Conclusion: Paediatric haematohidrosis is a rare, but clinically distinct condition. Treatment with Beta blockers may be tested.

Histological and functional comparisons of four anatomical regions of porcine skin with human abdominal skin.

Because of the shortage of human skin for research purposes, porcine skin has been used as a model of human skin. The aim of this study was to identify the region of German Landrace pig skin that could be used as the best possible substitute for human abdominal skin. Porcine samples were collected from the ear, flank, back and caudal abdomen; human abdominal skin samples were excised during plastic surgery. Histological and ultrastructural assessments were carried out on the epidermis and dermis, with emphasis on the dermo-epidermal interface length, dermo-epidermal thickness ratio as well as densities of; hair follicles, arrector pili muscles, blood vessels and sweat glands. In the pig, the barrier function of the four anatomical regions was assessed. Results showed that both histologically and ultrastructurally, all four regions of porcine skin were similar to human skin. These include the shapes of keratinocytes, structure of cell contacts and presence of Weibel Palade bodies in endothelial cells. Other parameters such as the thickness of epidermis, the thickness of stratum basale, spinosum and granulosum and the number of cell layers in the stratum corneum were similar in human abdominal and in all four regions of porcine skin. However, there were also significant differences especially in the thickness of the stratum corneum, the dermo-epidermal interface length and the blood vessel density.

Plexiform vascular structures in the human digital dermal layer: a SEM--corrosion casting morphological study.

This study aimed to describe the impressive diversity of vascular plexiform structures of the hypodermal layer of human skin. We chose the human body site with the highest concentration of dermal corpuscles, the human digit, and processed it with the corrosion casting technique and scanning electron microscopy analysis (SEM). This approach proved to be the best tool to study these microvascular architectures, free from any interference by surrounding tissues. We took high-definition pictures of the vascular network of sweat glands, thermoreceptorial and tactile corpuscles, the vessels constituting the glomic bodies and those feeding the hair follicles. We observed that the three-dimensional disposition of these vessels strictly depends on the shape of the corpuscles supplied. We could see the tubular vascularization of the excretory duct of sweat glands and the ovoid one feeding their bodies, sometimes made up of two lobes. In some cases, knowledge of these morphological data regarding the normal disposition in space and intrinsic vascularization structure of the dermal corpuscles can help to explain many of the physiopathological changes occurring during chronic microangiopathic diseases.

Innervation and vasculature of human sweat glands: an immunohistochemistry-laser scanning confocal fluorescence microscopy study.

Secreting tubules, nerves fibers, and blood vessels in human sweat glands (SGs) were fluorescently stained by immunohistochemical and lectin methods for examination with a laser scanning confocal microscope (LSCM). Using these techniques, the three-dimensional distribution of up to three substances within a single specimen was investigated by collecting a series of optical sections for each of three fluorophores. Each SG received several nerve fibers. These branched into delicate bands of one or more axons that ran longitudinal to the sweat tubule then encircled the tubule. A heavy complement of capillaries was interwoven among the sweat tubules. Sweat ducts were accompanied from the SG toward the skin surface by one or two longitudinally oriented nerve fibers and capillaries. Immunoreactive staining of nerves was heaviest with protein gene product 9.5 antibody, but triple labeling showed that immunoreactivity to calcitonin gene-related peptide, vasoactive intestinal polypeptide, and synaptophysin was also present in the same axons. Substance P-immunoreactive axons were sparse in SGs but were present in other areas of the skin. The techniques used have considerable potential in examination of human skin biopsies for diagnosis of disorders affecting the somatic and autonomic nervous systems.

Three-dimensional architecture of the microvasculature in the rat foot-pad, with special reference to vasculature around the eccrine sweat glands. A scanning electron-microscopic study of corrosion casts.

The entire microvascular architecture in rat foot-pads including that of eccrine sweat glands was studied by scanning electron microscopy using a vascular corrosion-cast replication technique. In the central roofs of the pads, particularly elaborate capillary networks were arranged in rows perpendicular to the long axis of the foot. In the marginal regions of the pads, simple networks of capillaries were arranged in lamellar sheets parallel to the surface of the sole of the foot. Complex spongy networks of vascular trees were observed in the subcutaneous layer of the pads. These vessels were supplied by the pad artery, and then, after forming capillary networks in the roofs of the pads, they drained into the metatarsal vein. Rod-shaped cages of capillaries were observed around the eccrine sweat glands. One descending arteriole, arising from a connecting arteriole, and a few venules were connected with these capillary cages at their upper and lateral sides. Occasional arterio-venous and veno-venous anastomoses were also observed around the eccrine sweat glands. This microvascular architecture may adjust well to the mechanical and physiological conditions encountered in the foot-pads. The relation of the microvascular architecture around the eccrine sweat glands with their development is also discussed.

Ultrastructure of the secretory epithelium, nerve fibers, and capillaries in the mouse sweat gland.

The ultrastructure of the mouse sweat gland was examined, in support of neurological studies of sweat glands and their relationships to the autonomic nervous system. It was found that the mouse sweat gland is similar to that of the rat and has only one type of secretory cell. Many nerve fibers are entwined with the secretory tubule and contain accumulations of round, clear vesicles, some microtubules, but apparently no neurofilaments. Cholinesterase is found in the clefts between nerve fibers and their ensheathing Schwann cells. The nerve fibers tend to run parallel with capillaries, but have no close association with either the capillaries or the secretory epithelium. Capillaries provide an abundant blood supply to the sweat gland and are fenestrated. The relationships between cellular elements of the sweat gland provide no direct evidence of the mechanisms involved in neurogenic sweating, although it seems likely that effector substances are diffusely distributed.

Immunoreactive glucagon in the vascular walls of the rat.

We detected immunohistochemically immunoreactive glucagon (IRG) in the smooth muscle of blood vessels and the myoepithelial cell of sweat glands of rats using two antisera against pancreatic glucagon; OAL-123 and 30K. The content of IRG in the blood vessels was found to be 320-1, 270 pg per g wet tissue weight. Filtration of the extracted IRG through a Bio Gel P-30 column yielded a single peak of IRG at 3,500 daltons, the same elution volume of pancreatic glucagon. These findings suggest that the blood vessels of the rats is one of the extrapancreatic sources of IRG in plasma, although physiological role of the IRG is not known.

Studies on the nature of the peripheral sudomotor control mechanism.

Electron microscopical studies of the sweat glands of the body surface of the cow, sheep, goat and cat demonstrated that there were few nerves or blood vessels near the glands. No varicosities were found within 10 micron of the glands, and the small number of unmyelinated nerve bundles traced were over 1.5 micron from the glandular myoepithelium, and situated outside a fibrocyte sheath surrounding the glands. It was concluded that the sweat glands of these species are not innervated. Unmyelinated nerve fibres were more abundant around, and were closer to, the sweat glands of man, the horse and cat footpads, and varicosities were observed within the fibrocyte sheath close enough to have a direct influence on the glands. It is postulated from the comparative evidence that the basic sudomotor mechanism is the same in all species, involving the action of adrenergic and cholinergic nerves on the cutaneous blood vessels and local catecholamine transfer to the gland; and that in species such as man where the blood supply and sympathetic nerves are in close proximity to the glands, transmitters released at the sympathetic nerve endings, in particular acetylcholine, will, in addition, have a direct action on the glands.

Arteriovenous anastomoses in the skin of tropical cattle.

As part of a general study of the vascular arrangement in the skin of cattle in tropical environments, the arteriovenous anastomoses (AVA) and other specialized vascular structures in the various skin sites of cattle were observed histologically. AVA were abundant in the skin from the scrotum, eye margin and the lower limb sites but were generally less numerous on the hairy body skin sites of cattle. Most of the AVA, especially those in the scrotal skin, were complex and tortuous S-shaped vessels, mainly located in the mid- and lower reticular layer and the mid- and lower papillary layer. The possible significance of their presence in various body sites, especially on the scrotal skin, is discussed.