Subclinical effects of botulinum toxin A and microwave thermolysis for axillary hyperhidrosis: A descriptive study with line-field confocal optical coherence tomography and histology.

Botulinum toxin A (BTX) and microwave thermolysis (MWT) are standard axillary hyperhidrosis treatments, but comparison of their subclinical effects is lacking. Line-field confocal optical coherence tomography (LC-OCT) is a promising non-invasive imaging tool for visualizing tissue-interactions. This study aimed to describe subclinical effects of BTX and MWT for axillary hyperhidrosis with LC-OCT-imaging compared to histology. This study derived from an intra-individual, randomized, controlled trial, treating axillary hyperhidrosis with BTX versus MWT. Subclinical effects based on LC-OCT images from baseline and 6-month follow-up (n = 8 patients) were evaluated and compared to corresponding histological samples. At baseline, LC-OCT visualized eccrine pores at the skin surface and ducts in the upper dermis (500 µm), but not deeper-lying sweat glands. Histology identified entire sweat glands. Six months post-treatment, LC-OCT revealed no detectable morphology changes in any BTX-treated axillae (100%), while recognizing obstructed eccrine pores and atrophy of eccrine ducts in most MWT-treated axillae (75%). Histology corroborated LC-OCT findings, while also showing substantial changes to entire sweat glands. LC-OCT enabled visualization of subclinical alterations of superficial eccrine ducts after MWT and unchanged morphology after BTX. LC-OCT is a promising tool for non-invasive assessment of treatment-specific tissue-interactions that can be complementary to histology.

Super-resolution algorithm for the characterization of sweat glands in fingerprint OCT images.

Optical coherence tomography (OCT) is a noninvasive optical imaging technique that can be used to produce three-dimensional images of fingerprints. However, the low quality and poor resolution of the regions of interest (ROIs) in OCT images make it challenging to segment small tissues accurately. To address this issue, a super-resolution (SR) network called ESRNet has been developed to enhance the quality of OCT images, facilitating their applications in research. Firstly, the performance of the SR images produced by ESRNet is evaluated by comparing it to those generated by five other SR methods. Specifically, the SR performance is evaluated using three upscale factors (2×, 3×, and 4×) to assess the quality of the enhanced images. Based on the results obtained from the three datasets, it is evident that ESRNet outperforms current advanced networks in terms of SR performance. Furthermore, the segmentation accuracy of sweat glands has been significantly improved by the SR images. The number of sweat glands in the top view increased from 102 to 117, further substantiating the performance of the ESRNet network. The spiral structure of sweat glands is clear to human eyes and has been verified by showing similar left-right-handed spiral numbers. Finally, a sweat gland recognition method for the SR 3D images is proposed.

A Simple Non-Contact Optical Method to Quantify In-Vivo Sweat Gland Activity and Pulsation.

OBJECTIVE: Most methods for monitoring sweat gland activity use simple gravimetric methods, which merely measure the average sweat rate of multiple sweat glands over a region of skin. It would be extremely useful to have a method which could quantify individual gland activity in order to improve the treatment of conditions which use sweat tests as a diagnostic tool, such as hyperhidrosis, cystic fibrosis, and peripheral nerve degeneration. METHODS: An optical method using an infrared camera to monitor the skin surface temperature was developed. A thermodynamics computer model was then implemented to utilize these skin temperature values along with other environmental parameters, such as ambient temperature and relative humidity, to calculate the sweat rates of individual glands using chemically stimulated and unstimulated sweating. The optical method was also used to monitor sweat pulsation patterns of individual sweat glands. RESULTS: In this preliminary study, the feasibility of the optical approach was demonstrated by measuring sweat rates of individual glands at various bodily locations. Calculated values from this method agree with expected sweat rates given values found in literature. In addition, a lack of pulsatile sweat expulsion was observed during chemically stimulated sweating, and a potential explanation for this phenomenon was proposed. CONCLUSION: A simple, non-contact optical method to quantify sweat gland activity in-vivo was presented. SIGNIFICANCE: This method allows researchers and clinicians to investigate several sweat glands simultaneously, which has the potential to provide more accurate diagnoses and treatment as well as increase the potential utility for wearable sweat sensors.

Automatic algorithm for the characterization of sweat ducts in a three-dimensional fingerprint.

In this study, an automatic algorithm has been presented based on a convolutional neural network (CNN) employing U-net. An ellipsoid and an ellipse were applied for approximation of a three-dimensional sweat duct and en face sweat pore at the different depths, respectively. The results demonstrated that the length and the diameter of the ellipsoid can be used to quantitatively describe the sweat ducts, which has a potential for estimating the frequency of resonance in millimeter (mm) wave and terahertz (THz) wave. In addition, projection-based sweat pores were extracted to overcome the effect that the diameters of en face sweat pores depend on the depth. Finally, the projection-based image of sweat pores was superposed with a maximum intensity projection (MIP)-based internal fingerprint to construct a hybrid internal fingerprint, which can be applied for identification recognition and information encryption.

The use of 33 MHz ultra-high-frequency ultrasonography for the evaluation of sweat glands in the axilla with osmidrosis.

BACKGROUND: This study aimed to assess the use of 33 MHz ultra-high-frequency ultrasonography (33MHz-UHFUS) for evaluating axillary sweat glands with osmidrosis in comparison with histological techniques. Axillary osmidrosis is a common problem in Asian societies, and the number and size of apocrine sweat glands have a strong relationship with osmidrosis severity. Currently, there are no methods to evaluate sweat gland distribution non-invasively. METHODS: In this study, 35 skin specimens from 10 fresh human cadavers without osmidrosis and retrospective ultrasonographic images from 20 patients with osmidrosis were used. Skin specimens were embedded in paraffin, thinly sliced, and finally stained with hematoxylin and eosin. Histologically, the apocrine and eccrine glands were evaluated, and the top and bottom depths of follicles were measured from the skin surface. In 33 MHz ultrasonography images, the depths of sweat glands were measured, and the mean grey value was calculated using Image J. RESULTS: Compared to histological data, 33MHz-UHFUS could be used to identify sweat glands as a hyperechoic structure between the dermis and fat layer. Furthermore, it could evaluate sweat gland distribution but could not distinguish between types of sweat glands. CONCLUSIONS: The distribution of sweat glands in the axilla can be non-invasively evaluated via 33MHz-UHFUS.

En-face optical coherence tomography/fluorescence endomicroscopy for minimally invasive imaging using a robotic scanner.

We report a compact rigid instrument capable of delivering en-face optical coherence tomography (OCT) images alongside (epi)-fluorescence endomicroscopy (FEM) images by means of a robotic scanning device. Two working imaging channels are included: one for a one-dimensional scanning, forward-viewing OCT probe and another for a fiber bundle used for the FEM system. The robotic scanning system provides the second axis of scanning for the OCT channel while allowing the field of view (FoV) of the FEM channel to be increased by mosaicking. The OCT channel has resolutions of 25 / 60 µm (axial/lateral) and can provide en-face images with an FoV of 1.6 × 2.7 mm2. The FEM channel has a lateral resolution of better than 8 µm and can generate an FoV of 0.53 × 3.25 mm2 through mosaicking. The reproducibility of the scanning was determined using phantoms to be better than the lateral resolution of the OCT channel. Combined OCT and FEM imaging were validated with ex-vivo ovine and porcine tissues, with the instrument mounted on an arm to ensure constant contact of the probe with the tissue. The OCT imaging system alone was validated for in-vivo human dermal imaging with the handheld instrument. In both cases, the instrument was capable of resolving fine features such as the sweat glands in human dermal tissue and the alveoli in porcine lung tissue.

CT-Guided Chemical Thoracic Sympathectomy versus Botulinum Toxin Type A Injection for Palmar Hyperhidrosis.

BACKGROUND: The present study aimed to evaluate and compare the efficacy of botulinum toxin type A (BTX-A) injection versus thoracic sympathectomy for idiopathic palmar hyperhidrosis. METHODS: Fifty-one patients with idiopathic palmar hyperhidrosis were treated with either BTX-A injection or thoracic sympathectomy between March 2013 and April 2016. The severity of palmar hyperhidrosis was qualitatively measured via the Hyperhidrosis Disease Severity Scale (HDSS). All patients completed a questionnaire that detailed the time taken for the treatment to work, local or systemic adverse effects, and pre- and post-treatment severity of hyperhidrosis. The efficacy and adverse effects of the two treatments were compared and analyzed. RESULTS: Hyperhidrosis-related quality of life improved quickly and significantly in the BTX-A group (26 patients) and the sympathectomy group (25 patients). Compared with pre-treatment, the HDSS score significantly reduced after treatment in both groups (p < 0.05). All patients in the sympathectomy group had cessation of sweating of the hands after treatment, and this curative effect lasted for 12 months. In contrast, the treatment took more time to work in the BTX-A group, and the curative effect lasted for a much shorter period (3 months). The sympathectomy group had a significantly lesser mean HDSS score than the BTX-A group at 1 week, 3 months, 6 months, 9 months, and 12 months after treatment (p < 0.05). The sympathectomy group experienced more complications than the BTX-A group. CONCLUSION: For palmar hyperhidrosis, thoracic sympathectomy is more effective and has a longer lasting curative effect than BTX-A injection, but thoracic sympathectomy has more complications.

Novel methods of imaging and analysis for the thermoregulatory sweat test.

The thermoregulatory sweat test (TST) can be central to the identification and management of disorders affecting sudomotor function and small sensory and autonomic nerve fibers, but the cumbersome nature of the standard testing protocol has prevented its widespread adoption. A high-resolution, quantitative, clean and simple assay of sweating could significantly improve identification and management of these disorders. Images from 89 clinical TSTs were analyzed retrospectively using two novel techniques. First, using the standard indicator powder, skin surface sweat distributions were determined algorithmically for each patient. Second, a fundamentally novel method using thermal imaging of forced evaporative cooling was evaluated through comparison with the standard technique. Correlation and receiver operating characteristic analyses were used to determine the degree of match between these methods, and the potential limits of thermal imaging were examined through cumulative analysis of all studied patients. Algorithmic encoding of sweating and nonsweating regions produces a more objective analysis for clinical decision-making. Additionally, results from the forced cooling method correspond well with those from indicator powder imaging, with a correlation across spatial regions of -0.78 (confidence interval: -0.84 to -0.71). The method works similarly across body regions, and frame-by-frame analysis suggests the ability to identify sweating regions within ~1 s of imaging. Although algorithmic encoding can enhance the standard sweat testing protocol, thermal imaging with forced evaporative cooling can dramatically improve the TST by making it less time consuming and more patient friendly than the current approach. NEW & NOTEWORTHY The thermoregulatory sweat test (TST) can be central to the identification and management of several common neurological disorders, but the cumbersome nature of the standard testing protocol has prevented its widespread adoption. In this study, images from 89 clinical TSTs were analyzed retrospectively using two novel techniques. Our results suggest that these improved methods could make sweat testing more reliable and acceptable for screening and management of a range of neurological disorders.

Prenatal Correction of X-Linked Hypohidrotic Ectodermal Dysplasia.

Genetic deficiency of ectodysplasin A (EDA) causes X-linked hypohidrotic ectodermal dysplasia (XLHED), in which the development of sweat glands is irreversibly impaired, an condition that can lead to life-threatening hyperthermia. We observed normal development of mouse fetuses with Eda mutations after they had been exposed in utero to a recombinant protein that includes the receptor-binding domain of EDA. We administered this protein intraamniotically to two affected human twins at gestational weeks 26 and 31 and to a single affected human fetus at gestational week 26; the infants, born in week 33 (twins) and week 39 (singleton), were able to sweat normally, and XLHED-related illness had not developed by 14 to 22 months of age. (Funded by Edimer Pharmaceuticals and others.).

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging.

OBJECTIVES: The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). METHODS: The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed. RESULTS: There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images. CONCLUSIONS: Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Sonographic appearance of an eccrine spiradenoma: A case report.

Eccrine spiradenoma is a rare, benign, adnexal skin tumor of the sweat gland, which may manifest in any part of the body. It is typically located in the dermal or the subcutaneous fat layer. Eccrine spiradenomas rarely progress to malignant transformation and only a few cases of malignant transformation have been reported. Due to its rarity, there have been few reports about the sonographic appearances of eccrine spiradenoma. We report the sonographic findings in one case of eccrine spiradenoma, located in the subcutaneous fat and the deep dermal layers of the upper arm in a middle-aged woman.

Dermoscopic features of endocrine mucin-producing sweat gland carcinoma.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is very rare, with only 61 cases reported to date. EMPSGC is considered to be a low-grade carcinoma of sweat gland origin. Dermoscopic findings of EMPSGC have not been previously reported. We report the first case of a man with EMPSGC, featuring dermoscopic findings. Dermoscopic examinations of the present EMPSGC lesion revealed tumor cell proliferation that appeared as pink ovoid nests and elongated epidermis that resembled a whitish-pink network. Another characteristic finding of the present lesion was the large red/blue globules in pink ovoid nests in the tumor. Those reflected lacunae containing secretory fluid with red blood cells. We think that the large red/blue globules in pink ovoid nests in our case could be a characteristic dermoscopic finding specific to EMPSGC. We dermatologists encounter many "pink nodules" at out-patient clinics. The present dermoscopic findings may be useful for the differential diagnosis of EMPSGC.

Speckle-modulating optical coherence tomography in living mice and humans.

Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo. As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution. Using SM-OCT, we reveal small structures in the tissues of living animals, such as the inner stromal structure of a live mouse cornea, the fine structures inside the mouse pinna, and sweat ducts and Meissner's corpuscle in the human fingertip skin-features that are otherwise obscured by speckle noise when using conventional OCT or OCT with current state of the art speckle reduction methods.

Old and New Approaches for Assessing Sweating.

The evaluation of sweating activities contributes to both medical services and social living. There are several old and new approaches for assessing sweating. These methods are mainly composed of adopted techniques that focus on detecting small amounts of water on the skin surface. For many years, the iodine-starch reaction has been applied in various settings to evaluate sweat on the skin surface. However, methodology based on the coloration of sweat is in a constant state of evolution, and multiple advancements have been made. Furthermore, common fingerprinting is not just used for obtaining personal-identifying information anymore as it can also provide scientifically important information for sweat-pore mapping and sweat-component analysis. Additionally, there are multiple techniques for the quantitative measurement of sweat volume and dynamic intravital imaging of sweat, and these are also continually evolving. This chapter provides an overview of the old and new approaches for assessing sweating.

Dyshidrotic Eczema and Its Relationship to Metal Allergy.

Dyshidrotic eczema, also known as dyshidrotic dermatitis or pompholyx, is characterized by pruritic, small tense vesicles mainly on the palmoplantar region and lateral and ventral surfaces of the fingers. While its etiology appears to be related to sweating, as dyshidrotic eczema often occurs in an individual with hyperhidrosis, and the spring allergy season, histologic examination shows an eczematous reaction around the sweat ducts which is not associated with abnormalities of the sweat ducts. More recently, the nomenclature of 'acute and recurrent vesicular hand dermatitis' has been proposed to reflect clinical features of dyshidrotic eczema. Although the exact etiology of dyshidrotic eczema remains unknown, given the presence of metal allergy in patients with dyshidrotic eczema and the improvement of the symptoms by removing metal allergen, metal allergy is regarded as one of the important potential etiologic factors for dyshidrotic eczema.