Assessment of skin barrier function in podoconiosis: measurement of stratum corneum hydration and transepidermal water loss.

BACKGROUND: Podoconiosis is a common cause of lymphoedema in barefoot workers in Ethiopia and other countries. It has severe consequences for patients' physical function, quality of life and economic status. AIMS: To investigate stratum corneum (SC) hydration and transepidermal water loss (TEWL) in patients with podoconiosis compared with controls. METHODS: In total, 55 patients and 20 controls were recruited. For each study subject, SC and TEWL measurements were taken, along with foot and lower leg circumferences. Measurements were compared between the patient and control groups. RESULTS: Foot circumferences tended to be higher in patients with podoconiosis, with the mean foot:leg circumference ratio being 1·19 (95% confidence interval 1·11-1·28) times that for controls (P = 0·001). There was no detectable difference between patients and controls in TEWL values (P > 0·05); however, SC hydration was significantly lower in patients vs. controls for the foot (P = 0·004) and lower leg (P = 0·046) sites. CONCLUSIONS: Patients with podoconiosis have significantly lower SC hydration in the skin of their lower legs and feet than controls, which may lead to cracking and splitting, and increased risk of lymphoedema and infection.

Clinical assessment of human lymph flow using removal rate constants of interstitial macromolecules: a critical review of lymphoscintigraphy.

Edema is a common clinical problem, and the daily avoidance of edema depends critically on the lymphatic system, which clears leaked plasma proteins and fluid from the interstitial compartment. There is often confusion as to the difference between chronic edema and lymphedema. Lymphedema is by definition primarily a disease of impaired lymphatic drainage and lymph flow, and progress in lymphedema research, currently an increasingly active field, requires a clinically viable method for the quantitative assessment of lymph drainage rate in patients. Measurement of the rate of clearance of a new protein marker, radiolabelled human immunoglobulin, from skin, subcutis, and muscle provides a way of measuring human lymph flow quantitatively and is the only viable clinical method currently available. Considerable strides have been made over the last 5-10 years in evaluating the method and its pitfalls, including potential complications such as vascular clearance, peripheral lymphovenous communications and label dissociation. The review assesses critically, for the first time, the evidence relating to the method: its pitfalls; human lymph flow in various healthy and oedematous tissues; and how this is altered in hyperfiltration edemas, inflammation, vasoconstriction and various primary and secondary human lymphedemas.

Lymphoedema: an underestimated health problem.

BACKGROUND: Lymphoedema/chronic oedema is an important cause of morbidity in the population, but little is known of its epidemiology and impact on patients or health services. AIM: To determine the magnitude of the problem of chronic oedema in the community, and the likely impact of oedema on use of health resources, employment and patient's quality of life. DESIGN: Questionnaire-based survey. METHODS: Health professionals from dedicated lymphoedema services, specific out-patient clinics, hospital wards and community services (GP clinics and district nurses) were contacted to provide information on patients from within South West London Community Trust. A subset of the identified patients was interviewed. RESULTS: Within the catchment area, 823 patients had chronic oedema (crude prevalence 1.33/1000). Prevalence increased with age (5.4/1000 in those aged > 65 years), and was higher in women (2.15 vs. 0.47/1000). Only 529 (64%) were receiving treatment, despite two specialist lymphoedema clinics within the catchment area. Of 228 patients interviewed, 78% had oedema lasting > 1 year. Over the previous year, 64/218 (29%) had had an acute infection in the affected area, 17/64 (27%) being admitted for intravenous antibiotics. Mean length of stay for this condition was 12 days, estimated mean cost pound 2300. Oedema caused time off work in > 80%, and affected employment status in 9%. Quality of life was below normal, with 50% experiencing pain or discomfort from their oedema. DISCUSSION: Chronic oedema is a common problem in the community with at least 100 000 patients suffering in the UK alone, a problem poorly recognized by health professionals. Lymphoedema arising for reasons other than cancer treatment is much more prevalent than generally perceived, yet resources for treatment are mainly cancer-based, leading to inequalities of care.

Spectrophotometric assessment of pigmented skin lesions: methods and feature selection for evaluation of diagnostic performance.

This study documents the optical reflectance characteristics of pigmented skin lesions and evaluates their potential for improving the differential diagnosis of malignant melanoma from benign pigmented skin lesions. Optical reflectance spectra in the wavelength range 320-1100 nm were obtained from 121 lesions already selected by expert dermatologists as suspicious of malignancy. Characteristic differences in spectra from benign and malignant lesions were studied. Feature extraction showed significant differences between lesion groups classified by histology. Seven of the most relevant features were used in the discriminant analysis of reflectance spectra from 15 melanoma and 32 compound naevi which resulted in a sensitivity of 100% and specificity of 84.4% when compared with histology. This simple objective technique appears to perform as well as the expert dermatologist and may improve the diagnostic accuracy of non-specialists such as trainees and GPs. Further prospective clinical study of reflectance spectrophotometry in a larger patient group is now required.

Computed tomography in the assessment of response to limb compression in unilateral lymphoedema.

In this prospective study computed tomography (CT) was used to monitor the response of compression therapy in 27 patients with chronic unilateral lymphoedema over a 12 week period. Computed tomography examination of abnormal and normal limbs (proximal and distal portions) was performed in the first, third and 12th weeks of treatment. Changes in cross-sectional area (CSA) and average densities of the different compartments within the proximal and distal portions of the abnormal limb were compared with the normal side. The most significant decrease in CSA occurred within the subcutaneous compartment of the distal portion (P = 0.002); the decrease in CSA of the proximal portion was also significant (P = 0.02) but changes in muscle and bone compartments were not significant. Significant differences in average density measurements of the subcutaneous and muscle compartments remained between normal and abnormal limbs following the conclusion of the study (P = 0.001 and P = 0.01, respectively). This study demonstrates that CT is a useful method for monitoring therapeutic response to compression therapy.

Assessment of truncal edema following breast cancer treatment using modified Harpenden skinfold calipers.

After initial treatment for breast cancer, lymphedema often affects the trunk as well as the arm. Evaluation of truncal swelling by the clinical "pinch test" of the posterior axillary fold is unreliable. Our aim was to develop an objective measurement, using modified Harpenden skinfold calipers. Standard Harpenden skinfold calipers exert a pressure of 12.6 g.mm-2, which rapidly squeezes edema fluid out of the skinfold. Springs were substituted to exert a lighter but relatively constant load (3.7 g.mm-2). Repeated skinfold thickness measurements on the same, normal subject then gave a relative standard deviation (r.s.d.) or coefficient of variation of 5%. The posterior axillary folds of 14 patients (age 56 +/- 13 (s.d.) years) with an average 30% arm swelling were measured using the same procedure. Readings were taken at 10 s, and again after 60 s of sustained application to assess the rate of creep, or deformation with time, attributed to displacement of pressurized interstitial fluid. Two patients had clinically observable axillary fold swelling. Eight patients, including the above two, showed axillary fold swelling by caliper measurement, defined as a 10% increase over the contralateral side (2 r.s.d.'s). Creep was greater on the affected side in all 14 patients. Thus, modified calipers can detect axillary fold edema, and thereby provide an objective method for assessing changes in swelling after lymphedema treatment.

Assessment of noninvasive tests of cutaneous vascular control in the forearm using a laser Doppler meter and a Finapres blood pressure monitor.

The control of human forearm cutaneous vascular resistance was examined using a combination of laser Doppler perfusion measurement and continuous Finapres blood pressure measurement. Tests which provoke changes in blood flow via different control mechanisms (local and neural) were applied in a group of ten healthy subjects. The purpose was to select from them a suitable (i.e. statistically significant) group to apply in cases where a disease process is suspected of interfering with the control of the skin circulation. Deep inspiration, immersion of the feet in water at 15 degrees C (both eliciting sympathetic vasoconstrictor nerve activity) and arm dependency (eliciting the local veni-arteriolar response) produced statistically significant, symmetrical increases in cutaneous vascular resistance in both arms (p < 0.05, Wilcoxon's test for paired differences). Similarly, post-ischaemic reactive hyperaemia (mediated by local vasodilator mechanisms) and indirect heating of the body (eliciting increased sympathetic vasodilator nerve activity) resulted in significant decreases in cutaneous vascular resistance (p < 0.01). When deep inspiration was repeated from a vasodilated baseline after indirect heating, the increases in cutaneous vascular resistance were smaller than those obtained before heating. Isometric handgrip exercise failed to produce a significant change in contralateral cutaneous vascular resistance (p > 0.05). There were no differences between right and left arms for any test (p > 0.05). The successful tests were subjected to power analysis in order to predict likely patient sample sizes required to demonstrate altered responsiveness at sites of microcirculatory disturbance compared with normal skin.

High frequency, high resolution B-scan ultrasound in the assessment of skin tumours.

Sixteen skin tumours and one BCG vaccination granuloma were examined by 20-MHz B-scan ultrasound. Images were compared with closely matched histological sections of excised lesions. The correlation between histology and ultrasound was excellent for maximum tumour depth measurements (r = 0.96, P < 0.0001), but less good for maximum width (r = 0.84, P < 0.0001) because of the elastic contraction of tissue at excision. Architectural detail of lesions on histological sections corresponded well with that on ultrasound images. There was a good correlation for heterogeneity (collagen distribution vs. echo pattern (r = 0.86, P < 0.0001)), and between collagen content and echogenicity of lesions (r = 0.69, P < 0.003). Strong correlations were also obtained for echogenicity vs. spacing of collagen bundles (r = -0.65, P < 0.005), echogenicity vs. collagen bundle size (r = 0.58, P < 0.02), and echogenicity vs. cellularity (r = -0.68, P < 0.003). Results for dermatofibroma were atypical, due to paradoxical low internal echogenicity and increased echo absorption. B-scanning is a reliable non-invasive method for assessing tumour dimensions, and has potential for the study of tumour characteristics for diagnostic purposes.