Studies on Skin Diseases and Normal Skin
Dobrev H. Mechanical properties in other dermatological diseases. In: Bioengineering of
the skin: skin biomechanics. Elsner P., Berardesca E., Wilhelm K-P. (eds) CRC Press,
Boca Raton, 2001: 215-228.
Dobrev H. In vivo study of skin mechanical properties in Raynaud’s phenomenon.
Skin Res Technol 2007, 13 (1): 91-94.
Background/aim: Raynaud’s phenomenon is usually the first symptom in patients with
systemic sclerosis and may precede skin changes by several months or years. Noninvasive measurements of skin elasticity are very sensitive and appropriate for objective
and quantitative evaluation of sclerodermatous skin. The aim of this study was to
investigate and compare the mechanical properties of the skin in patients with primary,
secondary and suspected secondary Raynaud’s phenomenon.
Materials/methods: A total of 63 patients were studied. They were classified as having
scleroderma-type nailfold capillary abnormalities - 17 with indurative phase of scleroderma
(Group 1), 9 with edematous phase of scleroderma (Group 2), 18 with suspected
secondary Raynaud’s phenomenon (Group 3), and as having Raynaud’s phenomenontype nailfold capillary abnormalities - 19 with primary Raynaud’s phenomenon (Group 4).
Thirty-nine sex- and age-matched healthy individuals with normal nailfold capillaroscopy
pattern were also studied as controls. Mechanical properties of the skin were evaluated
using a non-invasive suction device (Cutometer) equipped with a 2-mm probe.
Measurements were performed over 5 anatomic regions: cheeks, volar forearms, wrists,
hands and proximal phalanx of the fingers. The skin mechanical parameters analyzed
were distensibility (Uf), elasticity (Ua/Uf) and viscoelasticity (Uv/Ue).
Results: Most demonstrative changes were observed over volar forearms. Patients
included in Group 1, Group 2 and Group 3 were characterized by significantly lower Uf
and higher Uv/Ue compared to patient group 4 and controls. Patient groups 1 and 2
showed significantly lower Ua/Uf, as well. There were no significant differences in skin
mechanical parameters between patient group 4 and control group.
Conclusion: Mechanical properties of the skin in patients with suspected secondary
Raynaud’s phenomenon significantly differ from these in patients with primary Raynaud’s
phenomenon and resemble those in patients with edematous phase of scleroderma. Our
findings suggest that the non-invasive measurements of skin elasticity could be helpful in
identifying patients with Raynaud’s phenomenon at risk of developing systemic sclerosis.
Dobrev H. Clinical and instrumental study of the efficacy of a new sebum control
cream. J Cosmet Dermatol 2007 (in press)
Dobrev H. CAPI TEXT v.1 – data analysis software for nailfold skin capillaroscopy.
Folia Medica (Plovdiv) 2007 (in press)
Dobrev H. Application of Cutometer area parameters for study human skin fatigue.
Skin Res Technol 2005, 11 (2): 120-2.
Background/aim The age-related decrease of skin elasticity results in bigger fatigue of
adult skin than young skin after applying multiple stress at one and the same anatomic
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region. The aim of this study was to compare the informativeness of cutometer standard
R-parameters with new area-parameters regarding the age-related changes in human skin
fatigue.
Materials/methods A total of 40 healthy volunteers aged 12-82 years were studied.
Mechanical parameters of the skin were determined using non-invasive suction skin
elasticity meter (Cutometer). Measurements were made on temporal region and volar
forearm. Skin mechanical parameters analyzed by Win-cutometer MPA software were R3,
R4 and R9 (R-parameters), and F2 and F3 (area-parameters).
Results The adult skin was characterized by significantly higher values of R4, R9 and F2,
and lower F3 compared to young skin. R3 was not significantly altered. There were not
any sex-related differences. F2 correlated positively with parameters R3, R4 and R9, while
F3 correlated negatively with R4. A positive correlation within the parameters R3, R4 and
R9 was established at both anatomic regions.
Conclusion The non-invasive method applied can be useful for objective and quantitative
investigation of age-related changes in skin fatigue and evaluation of the effects of
cosmetic and antiaging topical products. The mechanical parameters R4 and F3 are most
indicative of human skin fatigue.
Dobrev H. Study of human skin mechanical properties by means of cutometer.
[Review] Folia Med (Plovdiv) 2002, 44 (3): 1-5.
Aim Cutometer is a commercially available non-invasive suction skin elasticity meter. The
purpose of the present article is do discuss some aspects of the biological informativeness
and interpretation of the results obtained under studying of skin mechanical properties
with cutometer.
Methods/Results Results of previously published in the literature studies on the
mechanical properties of healthy and diseased skin and their changes after external
influences are analyzed
Conclusion The cutometer method of investigation gives an objective and meaningful
information on the mechanical properties of healthy and diseased human skin.
Dobrev H. In vivo study of skin mechanical properties in patients with systemic sclerosis.
J Am Acad Dermatol 1999, 40 (3): 436-442.
Background Measurements of skin elasticity are more sensitive than the skin severity
score and appropriate for evaluation of sclerodermatous skin.
Objective: Our purpose was to investigate the mechanical properties of the skin in patients
with systemic sclerosis depending on the stage of the disease.
Methods Seventeen patients, 8 with edematous phase and 9 with indurative phase of skin
involvement, and 16 healthy subjects were studied. Clinical scoring of skin thickness and
measurements of skin elasticity with a noninvasive suction device (Cutometer) were
performed over 11 anatomic regions.
Results Edematous phase was characterized by significantly lower immediate distension
(Ue) and final distension (Uf), and higher viscoelastic to elastic ratio (Uv/Ue) of the skin
compared with indurative phase, except for the forehead (8 mm probe). The changes in
skin mechanical parameters for fingers were identical in both phases. Low values of skin
distensibility correlated with severe skin thickness or hidebound skin. Results were
influenced by body site and by the diameter of measuring probe used.
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Conclusion The noninvasive method applied is suitable for objective and quantitative
monitoring of skin involvement in patients with systemic sclerosis.
Dobrev H. Value of the noninvasive skin bioengineering methods in patients with
scleroderma. [Review] Rheumatology (Bulgaria) 1998, 6 (2): 15-17.
Modern bioengineering methods provide an objective information regarding the degree of
the skin involvement and disturbances of the microcirculation in systemic and localized
sclerosis. They are characterized by noninvasiveness, that allows repeated
measurements, and achieving quantitative data subjected to statistical analysis. The
changes in skin thickness and density can be evaluated by high-frequency ultrasound,
nuclear magnetic resonance and elastometry. Microangiopathy can be studied by
capillaroscopy, laser-doppler flowmetry, measurements of transcutaneous oxygen tension,
thermometry and thermography. Noninvasive skin bioengineering methods are useful in
monitoring the therapy effect and disease progression in patients with scleroderma.
Dobrev H. In vivo study of skin mechanical properties in Scleredema of Buschke. Acta
Derm Venereol (Stockh) 1998, 78 (2): 103-106.
A non-invasive, in vivo suction device was used to investigate the mechanical properties
of the skin in a patient with scleredema of Buschke. Clinical scoring of skin induration and
measurements of skin elasticity were performed over 9 anatomic regions on admission
and after 3 (on discharge), 17 and 28 months. Immediate distension, final distension and
immediate retraction were significantly decreased, while the viscoelastic to elastic ratio
was significantly increased in the patient as compared to the healthy controls. Delayed
distension and biological elasticity were preserved. Low values of skin distensibility
correlated with a severe skin induration (p<0.001). The changes were more expressive
with the 8 mm-diameter measuring probe than the 2 mm-diameter probe. The method
applied can be used for objective and quantitative assessment of skin involvement in
scleredema of Buschke.
Grudeva-Popova J, H. Dobrev. Biomechanical measurement of skin distensibility in
scleredema of Buschke associated with multiple myeloma. Clin Exp Dermatol 2000, 25
(3): 247-249.
We report a case of scleredema of Buschke associated with IgG kappa monoclonal
hypergammaglobulinaemia. After myeloma polychemotherapy an improvement in skin
involvement was observed and confirmed by means of non-invasive skin elasticity
measurements. This suggests a relationship between the two diseases. The
bioengineering method used can be useful for early detection and monitoring the skin
involvement in patients with this disease association.
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Dobrev H. Scleroedema Buschke с 36 годишно протичане. [Scleredema of Buschke with
a 36-year duration] 8ht Annual Sofia dermatological days, November 5-7, 1999, Sofia,
Bulgaria. Dermatol Venereol (Bulgaria) 1999, 38 (2): 38. (Summary)
Dobrev H. In vivo study of skin mechanical properties in psoriasis vulgaris. Acta Derm
Venereol 2000, 80 (4): 263-266.
The aim of this study was to investigate the mechanical properties of the skin in psoriatic
plaques before and after treatment with dithranol and in clinically uninvolved psoriatic skin
in comparison with the skin of healthy controls. In total, 82 psoriatic plaques in 19 inpatients and 51 age-matched control subjects were studied with a non-invasive suction
device (Cutometer). The plaques were characterized by statistically significant lower skin
distensibility and elasticity, and a higher viscoelastic to elastic ratio compared with
adjacent apparently normal skin. Delayed distension and hysteresis measured using a 2mm diameter probe were decreased, but were increased when measured by a 8-mm
diameter probe. These differences can be explained by the increased skin thickness in
psoriasis and by the different aspects of skin mechanics determined by the 2 measuring
probes. After treatment, the mechanical parameters of psoriatic plaques approached the
values of adjacent control skin. The uninvolved volar forearm skin in psoriatic patients (2mm diameter probe) showed statistically significant lower values of skin distensibility and
higher values of viscoelasticity parameters compared with the skin of healthy control
subjects. This suggests that the normal-appearing psoriatic skin is not entirely normal. The
non-invasive method applied can be used for objective and quantitative evaluation of the
effect of therapy in patients with psoriasis.
Dobrev H. Changes in epidermal water content in patients with psoriasis vulgaris.
Scientific Researches of the Union of Scientists – Plovdiv. Series D. Medicine,
Pharmacy and Stomatology, Vol. 1. (Plovdiv) 2002: 107-110.
Aim The aim of this study was to determine the epidermal water content in lesional and
perilesional psoriatic skin before and after treatment with dithranol.
Materials and Methods. A total of 96 psoriatic plaques in 22 in-patients (4 women, 18 men,
aged 27-82 years, with disease duration of 1-35 years and PASI score of 4.1-32.6) were
studied. Epidermal hydration was determined by means of non-invasive skin capacitance
meter (Corneometer CM 820, Courage+Khazaka, Cologne, Germany). Measurements
were performed before and after 18±7-day treatment with dithranol.
Results The average values of electrical capacitance of psoriatic plaques (n=96) and
adjacent healthy skin were 29.8±9.4 АЕ and 64.1±11.5 АЕ, respectively (P<0.001). After
treatment, the values of electrical capacitance of psoriatic plaques (n=54) increased from
27.2±8.7 АЕ to 40.2±14.0 АЕ (Р<0.001), while those of perilesional skin did not
significantly change and were 63.5±11.3 and 64.9±11.9 АЕ, respectively.
Conclusion Pathologic epidermis in psoriasis vulgaris is characterized by low water
content, which increases after treatment with dithranol but remains lower than the water
content of adjacent healthy skin.
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Dobrev H. Use of cutometer to assess dermal oedema in erysipelas of the lower legs.
Skin Res Technol 1998, 4 (3): 155-159.
Background/Aims Inflammatory dermal oedema in erysipelas alters skin mechanics. The
aims of this study were to determine the relationship between the skin mechanical
properties and the changes in dermal water content in patients with erysipelas of the lower
leg, and to assess the value of measuring skin elasticity in monitoring the effect of
therapy.
Patients/Methods Twenty-five in-patients were studied before the treatment and after 10
and 20 days. Visual scoring of oedema, measurements of limb circumference and skin
elasticity with a non-invasive, suction device (Cutometer) were made on the affected and
unaffected lower legs.
Results Indurated skin was characterized by raised delayed distension (Uv), final
distension (Uf), resilient distension (R), viscoelastic to elastic ratio (Uv/Ue) and hysteresis
(H) and lower immediate distension (Ue), immediate retraction (Ur), gross elasticity
(Ua/Uf) and biological elasticity (Ur/Uf). The visual score of oedema and leg circumference
significantly correlated with the increase in Uv, Uv/Ue and H and the decrease in Ua/Uf
and Ur/Uf. The large 8 mm diameter measuring probe produced more pronounced
changes than the small 2 mm probe. As a result of treatment, a significant reduction in
viscoelastic parameters (Uv, Uv/Ue, R, H) and an increase in elastic parameters (Ua/Uf,
Ur/Uf) was observed.
Conclusion The non-invasive method applied is suitable for objective assessment of
dermal oedema and disease evolution in patients with erysipelas.
Dobrev H. Comparative study of the skin mechanical properties in erysipelas of the
lower legs using suction method and share wave propagation method. 13th
Congress European Academy of Dermatology & Venereology (EADV), November 1721, 2004, Florence, Italy.
Background/aim Inflammatory dermal edema in erysipelas alters skin mechanics. The
aim of this study was to compare the informativeness of two different methods for
evaluation of skin mechanical properties.
Methods Ten in-patients were studied prior to and after the treatment. Skin viscoelasticity
was evaluated on the affected and unaffected lower legs using a suction device
(Cutometer) equipped with two probes and resonance running time measurements
(RRTM) using the Reviscometer.
Results Affected skin was characterized by significantly lower cutometer elastic Rparameters (Ur, Ua/Uf and Ur/Uf), higher viscoelastic R-parameters (Uv, Uv/Ue, R8 and
hysteresis) and higher area-parameters (F0, F2 and F4). After treatment, the indicated
parameters significantly changed toward to those of the normal skin. The 8 mm-diameter
cutometer probe produced more pronounced changes than the smaller 2 mm-diameter
probe. The initial RRTM values were similar on both lower legs. The treatment induced a
significant decrease in multidirectional RRTM on the affected skin (-10.8%) which is due to
the marked decrease in the minimum RRTM (-20.3%). The last indicates an increase in
shear wave velocity predominantly in the direction of skin tension lines, i.e., increased
intrinsic tension inside the skin, and suggest an improvement of skin elasticity.
Conclusion Simultaneously measurements of skin mechanical properties by means of
suction method and shear wave propagation method are useful tool for objective
evaluation of the skin changes in patients with erysipelas.
Acknowledgement: The author would like to thank Courage+Khazaka Electronic, Köln,
Germany for supplying with the Cutometer MPA 580 and Reviscometer RVM 600.
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Dobrev H. Syndroma Ehlers-Danlos - механични свойства на кожата. [Syndroma
Ehlers-Danlos – mechanical properties of the skin] Xht Annual Sofia dermatological
days, November 2-3, 2001, Sofia, Bulgaria. Dermatol Venereol (Bulgaria) 2001, 40 (2):
27. (Summary)
Dobrev H. Fasciitis eosinophilica - механични свойства на кожата. [Fasciitis
eosinophilica – mechanical properties of the skin] Xht Annual Sofia dermatological
days, November 2-3, 2001, Sofia, Bulgaria. Dermatol Venereol (Bulgaria) 2001, 40 (2):
28. (Abstract)
Dobrev H. Study of human skin mechanical properties by means of cutometer. [Review]
Folia Med (Plovdiv) 2002, 44 (3): 1-5.
Aim Cutometer is a commercially available non-invasive suction skin elasticity meter. The
purpose of the present article is do discuss some aspects of the biological informativeness
and interpretation of the results obtained under studying of skin mechanical properties
with cutometer.
Methods/Results Results of previously published in the literature studies on the
mechanical properties of healthy and diseased skin and their changes after external
influences are analyzed
Conclusion The cutometer method of investigation gives an objective and meaningful
information on the mechanical properties of healthy and diseased human skin.
Dobrev H. Study of human skin fatigue. Scientific Researches of the Union of
Scientists – Plovdiv. Series D. Medicine, Pharmacy and Stomatology, Vol. 2. (Plovdiv)
2003: 84-87.
Aim The aim of this study was to determine the age-related changes in skin fatigue.
Materials/Methods A total of 40 healthy volunteers aged 12-82 years was studied. They
were divided into 4 groups: 10 young men (mean age of 18.7±5.4 years), 10 young
women (mean age of 20.7±5.5 years), 10 elderly men (mean age of 70.9±7.2 years) and
10 elderly women (67.8±6.8 years). Measurements were made on the right temporal
region and volar forearm by means of a non-invasive suction skin elasticity meter
(Cutometer SEM 474, Courage+Khazaka, Cologne, Germany). We used a 2 mm-diameter
measuring probe and applied a constant suction of 400 mbar for 1 s followed by relaxation
time of 1 s, 30 repetitions. Eight skin mechanical parameters were analyzed.
Results At the two anatomical regions aged skin showed statistically significant higher
values of the mechanical parameters R1, R4, R3-R0, R4-R1, R0-(R3-R10) and
significantly lover values of the parameters R0-R1, R3-R4, R3-R10 compared to young
skin. There were not established any sex-related differences.
Conclusion Skin aging induces progressive decrease in the skin capability to restore its
initial shape after multiple deformations, i.e. the aged skin is characterized by greater
fatigue than young skin.
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Dobrev H. Application of Cutometer area parameters for study human skin fatigue.
II. Spring Symposium of the European Academy of Dermatology and Venereology
(EADV), April 29 – May 1, 2004, Budapest, Hungary. J Eur Acad Dermatol Venerol
2004, 18, Suppl.1: 53.
Background/aim The age-related decrease of skin elasticity results in bigger fatigue of
adult skin than young skin after applying multiple stress at one and the same anatomic
region. The aim of this study was to compare the informativeness of cutometer standard
R-parameters with new area-parameters regarding the age-related changes in human skin
fatigue.
Materials/methods A total of 40 healthy volunteers aged 12-82 years were studied.
Mechanical parameters of the skin were determined using non-invasive suction skin
elasticity meter (Cutometer). Measurements were made on temporal region and volar
forearm. Skin mechanical parameters analyzed by Win-cutometer MPA software were R3,
R4 and R9 (R-parameters), and F2 and F3 (area-parameters).
Results The adult skin was characterized by significantly higher values of R4, R9 and F2,
and lower F3 compared to young skin. R3 was not significantly altered. There were not
any sex-related differences. F2 correlated positively with parameters R3, R4 and R9, while
F3 correlated negatively with R4. A positive correlation within the parameters R3, R4 and
R9 was established at both anatomic regions.
Conclusion The non-invasive method applied can be useful for objective and quantitative
investigation of age-related changes in skin fatigue and evaluation of the effects of
cosmetic and antiaging topical products. The mechanical parameters R4 and F3 are most
indicative of human skin fatigue.
Dobrev H. Photoaging and skin elasticity. Research Reports of the Union of Scientists
in Bulgaria – Plovdiv. Annual, Series B. Natural Sciences and Humanities, Vol. 1.
(Plovdiv) 2000: 117-120.
The aim of the present study was to determine the effect of chronic sun exposure on the
skin mechanical properties. We studied 73 volunteers (37 men, 36 women, aged range
10-79 years, mean age 41 years) by means of a noninvasive suction skin elasticity meter
(Cutometer). Sun-exposed skin of the dorsal forearm showed a significantly lower
distensibility and biological elasticity than the unexposed volar forearm skin. These
changes are related to the massive increase and disorganization of the elastic tissue,
which are accompanied by lost of functional elastic fibers. The later plays an important
role in maintaining the collagen fiber network, in controlling the movements of this network
within the ground substance and in restoring the initial position of the skin after
deformation. On both anatomical regions skin elasticity decreased and viscoelasticity
increased with the age.
Dobrev H. Age related changes in the mechanical properties of human skin. Dermatol
Venereol (Bulgaria) 1999, 38 (2): 21-25.
We used a non-invasive, in vivo suction skin elasticity meter to investigate age-related
skin mechanical properties on 12 anatomic regions. A total of 40 volunteers was studied
consisting of 10 young males, 10 old males, 10 young females and 10 young males. The
parameters determined were Ue, immediate distension; Uv, delayed distension; Uf, final
8
distension; Ur, immediate retraction; Ua, final retraction; R, residual deformation and their
relations Ua/Uf, brut elasticity; Ur/Ue, net elasticity; Ur/Uf, biological elasticity; Uv/Ue,
viscoelastic to elastic ratio and H, hysteresis. Aged skin was characterized by significantly
lower elastic parameters (Ue, Uf, Ur, Ua/Uf, Ur/Ue, Ur/Uf) and higher viscoelastic
parameters (Uv, Uv/Ue, H, R). On all the anatomic regions, the decrease in skin elasticity
and the increase in skin viscoelasticity significantly correlated with the age. The changes
were more pronounced on the sun-exposed sites. There were no sex differences. The
method used is suitable for investigation of aging process and efficacy of topical
preparations applied.