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Actions of Dopamine on the Skin and the Skeleton
Published in Nira Ben-Jonathan, Dopamine, 2020
Apocrine glands are found in the armpits, areola of the breast, perineum (area between anus and genitals), in the ear, and in the eyelids. Eccrine glands are present all over the body, except for the abovementioned parts. Apocrine sweat glands secrete a fluid containing pheromone-like compounds that attract the opposite sex. This phenomenon occurs in all mammals, including humans. A distinguishing feature of apocrine glands is that they are inactive before puberty. The hormonal surge during puberty brings about a change in the size of the apocrine glands and starts their functioning. In sum, apocrine glands are considered as modified glands that secrete wax in the ears, milk in the breast and secretions of the ciliary glands in the eyelids, while eccrine glands are the major sweat glands of the body and are widely distributed.
Eyelids
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
Omar Kouli, Mostafa Khalil, Stewart Gillan
The adnexa lie deep in the dermis and includes the eyelashes and many types of glands: Eccrine glands: Sweat glands.Apocrine glands: Modified sweat glands (e.g. gland of Moll).Holocrine glands: Gland of Zeis, and meibomian glands. These glands synthesize/secrete lipids and oily substances.
Sjögren syndrome and mixed connective tissue disease
Published in Biju Vasudevan, Rajesh Verma, Dermatological Emergencies, 2019
Cutaneous features of Sjögren syndrome include xerosis, Raynaud phenomenon, cutaneous vasculitis, and annular erythema (Table 43.1). Xerosis of skin is the most common cutaneous finding in patients with Sjögren syndrome, occurring in 23%–67% patients [5,6]. Dry skin is prone to itching, and chronic scratching can lead to lichenification (Figure 43.1). Initially thought to be due to reduced sweating because of lymphocytic infiltration of the eccrine glands, xerosis in Sjögren syndrome is now believed to occur as a result of alterations in the stratum corneum layer [7]. Cutaneous vasculitis is reported in about 10%–30% patients, and usually affects the small-caliber vessels presenting as palpable purpura or urticarial lesions. Medium vessel involvement is infrequent and is often associated with cryoglobulinemia [8,9]. Annular erythema of Sjögren syndrome favors head and neck, and morphologically resembles the annular papulosquamous skin lesions in subacute cutaneous lupus erythematosus. Its histopathology shows perivascular and periappendigeal lymphocytic infiltrate, while lacking the interface changes of lupus erythematosus. It has been mostly reported in Japanese cohorts and is more common in patients with antibodies against SS-A/SS-B [10–12]. Other skin findings can include vitiligo, lichen planus, cutaneous amyloidosis, livedo reticularis, and erythema nodosum [4,5]. Patients with secondary Sjögren syndrome can have additional manifestations depending on the associated autoimmune disease.
Cannabinoids in hyperhidrosis
Published in Journal of Dermatological Treatment, 2023
Till Kaemmerer, Benjamin Maximilian Clanner-Engelshofen, Tony Lesmeister, Lars Einar French, Markus Reinholz
Although cannabinoid therapy indications are steadily increasing, our understanding of the underlying pharmacodynamics is still incomplete. Cannabinoids bind to G protein-coupled cannabinoid receptors CB1 and CB2. CB1 receptors are primarily distributed in the peripheral and central nervous systems, and among other effects, inhibit presynaptic neurotransmission. The CB2 receptors, on the other hand, are localized predominantly in the peripheral immune and nervous system and have an inhibitory effect. We speculate one effect of cannabinoids in primary hyperhidrosis is presynaptic inhibition of acetylcholine release, and thus, diminished sweat secretion. The pathophysiology of hyperhidrosis does not seem to involve eccrine glands directly, as evidenced by a lack of histopathological changes. Instead, data points to neuronal overexcitations in the context of a more involved autonomic dysfunction (1,13). These hypotheses require validation.
A systematic evidence-based review of treatments for primary hyperhidrosis
Published in Journal of Drug Assessment, 2021
Michael E. Stuart, Sheri A. Strite, Kristin Khalaf Gillard
The protocol for this systematic review was registered in PROSPERO International Prospective Register of Systematic Reviews (crd.york.ac.uk/prospero/index.asp identifier CRD42018104063). Clinical trials were eligible for inclusion. Eligibility was based on the Cochrane PICO annotation system13: population (patients with primary hyperhidrosis involving axillae, palms, soles or head without age restriction), intervention (four interventions used in the treatment of primary hyperhidrosis of the head, axilla, palms and soles in children and adults – see Figure 1), comparator (placebo, no treatment or any of the commonly used treatments listed above), outcome (efficacy, safety and quality of life outcomes using a variety of tools reported in the literature). Non-English language studies were excluded. Treatments evaluated include aluminum and zirconium compounds, anticholinergics (topical and systemic), botulinum toxin, and medical device therapies designed to alter the function of sweat production or damage eccrine glands (iontophoresis, curettage, laser therapy, microwave, fractional needle radiotherapy and ultrasound; Figure 1).
Physiology of sweat gland function: The roles of sweating and sweat composition in human health
Published in Temperature, 2019
The eccrine glands are functional early in life and, starting at ~2–3 years of age, the total number of eccrine glands is fixed throughout life [12–14]. Therefore, overall sweat gland density decreases with skin expansion during growth from infancy and is generally inversely proportional to body surface area. As a result, children have higher sweat gland densities than adults [11], and larger or more obese individuals have lower sweat gland densities than their smaller or leaner counterparts [13,17]. However, higher sweat gland density does not necessarily translate to higher sweating rate. In fact, most of the variability in regional and whole-body sweating rate within and between individuals is due to differences in sweat secretion rate per gland, rather than the total number of active sweat glands [18,19]. Eccrine sweat is mostly water and NaCl, but also contains a mixture of many other chemicals originating from the interstitial fluid and the eccrine gland itself. The structure and function of eccrine glands and the composition of eccrine sweat will be discussed in more detail in subsequent sections of this paper.