Effect of Occlusive Dressings on the Stratum
`Corneum Water Holding Capacity
`
`ENZO BERARDESCA,*
`DOMENICO FIDELI,*
`
`GIAN PIERO VIGNOLl,*
`HOWARD MAIBACHt
`
`ABSTRACT: Occlusion of the skin is used in
`clinical dermatology to promote wound healing
`and to increase the transcutaneous penetration
`of topically applied drugs. These effects are re(cid:173)
`lated to the degree of occlusion exerted and de(cid:173)
`pend on the physicochemical nature of the dress(cid:173)
`ing. We have evaluated the effects of four differ(cid:173)
`ent materials on the skin barrier and the stratum
`corneum water holding capacity (WHC) using the
`Plastic Occlusion Stress Test (POST). The fol(cid:173)
`lowing materials were compared: hydrocolloid
`dressing, polyurethane film, polyethylene film,
`and a plastic chamber. These devices were ap(cid:173)
`plied on the volar forearm for 24 hours in 10
`healthy volunteers (mean age 32 ± 4 years).
`Upon their removal, the stratum corneum WHC,
`measured as skin surface water loss (SSWL), was
`recorded continuously for 25 minutes using an
`Evaporimeter.
`SSWL decay curves showed significant differ(cid:173)
`ences between the occlusive materials (analysis
`of variance, p < 0.01). Higher SSWL values were
`recorded in sites occluded with the plastic cham(cid:173)
`ber, whereas the polyurethane film resulted in
`poor occlusive capacity. Hydrocolloid dressing
`and polyethylene gave similar responses with
`higher WHC values compared to polyurethane (p
`< 0.05). The relevance of these findings to
`clinical dermatology in terms of wound healing
`and drug absorption is discussed. KEY INDEX(cid:173)
`ING TERMS: Occlusion; Skin physiology; TEWL.
`[Am J Med Sci 1992;304(1):25-28.]
`
`S kin occlusion alters skin physiology and biology,
`
`eg, epidermal turnover, wound healing, and mi-
`
`From the *Department of Dermatology, University of Pavia, IRCCS
`Policlinico S. Matteo, Pavia, Italy, and the tUniversity of California,
`San Francisco.
`This report was supported in part by The Foundation for Research
`in Dermatology, Rome, Italy.
`Correspondence: Enzo Berardesca, Dept. of Dermatology, University
`of Pavia, Policlinico S. Matteo, 27100 Pavia, Italy.
`
`THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES
`
`crobial flora. l Occlusion accelerates the healing rate of
`superficial wounds. The effect may be a result of in(cid:173)
`creased cell migration across the surface2
`•3 or of in(cid:173)
`creased collagen synthesis and re-epithelialization.4
`Epidermal turnover is decreased after occlusion.5•6 In(cid:173)
`deed, occlusive therapy is used to treat hyperprolifer(cid:173)
`ative skin disorders such as psoriasis.6
`Several dressings are commercially available to treat
`skin disease. All claim to bring about improvement of
`the skin condition related to the occlusive effect.
`In the present study, we compared the effect of dif(cid:173)
`ferent dressings on skin hydration and stratum cor(cid:173)
`neum water holding capacity, and hence the occlusive
`capabilities of these products. Skin occlusion results
`in increased hydration because of inhibition of water
`evaporation. Hydration achieved by occlusion results
`in an increased transepidermal water loss (TEWL) post
`dressing removal. 7 TEWL measurements of the evap(cid:173)
`oration of water from the skin surface after occlusion
`quantifies the skin water holding capabilities and is an
`indirect measurement of the in vivo water content.s
`Materials and Methods
`Occlusive devices tested were: polyethylene film
`(Saran Wrap), polypropylene plastic chamber (18 mm
`diameter; Hill Top, Cincinnati, OH), hydrocolloid
`dressing (Duoderm; Convatec Squibb, Rome, Italy),
`and polyurethane film (Tegaderm; 3M, St. Paul, MN).
`Ten healthy male subjects (mean age 32 ± 4 years)
`entered the study. Subjects rested 30 minutes prior to
`the procedures. Occlusive dressings were applied on
`the volar forearm (left or right, randomized), each on
`a 4 cm2 surface (Figure 1). The application sequence
`was randomized to minimize hydration differences re(cid:173)
`sulting from site. After 24 hours, the dressings were
`removed. The Evaporimeter probe (ServoMed Ep-l,
`Kinna, Sweden) was immediately applied on the pre(cid:173)
`viously occluded site and TEWL was measured con(cid:173)
`tinuously every minute for 25 minutes. The probe was
`equipped with a gold-plated protection cover with grid
`(no. 2107) provided by the manufacturer. To avoid
`heating, the probe was held on the investigation site
`with a clamp.
`Skin temperature was measured on the two forearms
`with an electronic thermometer (Omega Corp., Stam-
`
`25
`
`

`

`Occlusion and Water Holding Capacity
`
`Figure 1. Occlusive dressings
`that have been compared to
`polyethylene:
`(1) plastic
`chamber; (2) hydrocolloid; and
`(3) polyurethane (see Materials
`and Methods) .
`
`ford, CT). TEWL values were transformed to loga(cid:173)
`rithms, and values were normalized for a temperature
`of 30° C, according to Mathias et al.9 Skin surface water
`loss decay constants were calculated according to
`Wagner. lO The one compartment open model with
`first order absorption was used. TEWL values are in
`g/m2hr.
`Statistical analysis of the data was performed using
`one way analysis of variance and Fisher's PLSD test.
`The level of p < 0.05 was considered significant. Cal-
`
`culations were performed with a software package for
`statistical analysis (Statview II; Abacus Concepts, Inc.,
`Berkeley, CA).
`
`Results
`Results are in Figure 2 and in Tables 1 and 2.
`Significant differences in TEWL values at the 1st
`and 25th minutes were detected among the dressings
`(analysis of variance = p < 0.01). The highest values,
`representing the highest hydration, were achieved in
`
`1,60e+8,----------------------------------------------------,
`
`+ +
`
`+ • • o
`
`plastic chamber
`hydrocolloid
`polyurethane
`polyethylene
`
`a
`
`" 8
`
`+ + +
`
`+ + +
`" 8 a a I a a
`
`+ + +
`
`• • • • • • • • • • • • • • • • • • • • •
`
`Figure 2. Transepidermal water
`loss (TEWL) decay curves after
`removal of the dressings (values
`in log g/m2h). Polyurethane film
`shows the lowest decay curve be(cid:173)
`cause of the least occlusive ca(cid:173)
`pability compared to the other
`dressings.
`
`1.40e+8 -
`
`1,20e+8 -
`
`• +
`
`+
`
`+
`0 •
`o •
`o a
`
`....J
`~
`UJ
`~
`
`8,OOe+7 -
`
`6,OOe+7 -
`
`4.00e+7
`
`I
`
`I,OOe+8 - • •
`•
`•
`
`I
`
`,
`
`I
`
`•
`
`I
`
`•
`
`,
`
`•
`
`• • •
`
`•
`
`I
`
`•
`
`I
`
`• • • I
`
`I 2 3 4 5 6 7 8 9 lOll 12131L151c1718192C2122232~25
`t1me
`
`26
`
`July 1992 Volume 304 Number 1
`
`

`

`Berordesco et 01
`
`the site occluded with polypropylene chamber (log
`TEWL = 1.52 and .87 at 1 and 25 minutes, respec(cid:173)
`tively), whereas the lowest were recorded on the site
`occluded with polyurethane (log TEWL = 1.0 and .59
`at 1 and 25 minutes, respectively; Table 1). Polyure(cid:173)
`thane film produced less occlusion than the plastic
`chamber, hydrocolloid dressing, and polyethylene
`(Fisher's PLSD, p < 0.05). At the 1st minute, the plastic
`chamber was significantly higher (Fisher's PLSD, p
`< 0.05) than polyethylene, but not higher than the hy(cid:173)
`drocolloid dressing.
`Decay constants of water evaporation from skin sur(cid:173)
`face are represented in Table 2. Statistically, polyure(cid:173)
`thane has the lowest decay constant of evaporation (p
`< 0.05) compared to the plastic chamber and the hy(cid:173)
`drocolloid dressing.
`
`Discussion
`Occlusive devices are used in clinical practice for the
`treatment of wound healing and psoriasis. Their ther(cid:173)
`apeutic effect is related to their occlusive capabilities.
`Skin occlusion on wounded skin causes increased pro(cid:173)
`duction of collagen, and consequently increased wound
`healing rate.4 The role of oxygen tension beneath the
`tape is controversial. Rapid reepithelialization is re(cid:173)
`ported when P02 is raised and when wounds are treated
`with oxygen permeable dressings.11 Nevertheless, a re(cid:173)
`duced P02 stimulates angiogenesis and fibroblast
`growth.12 Occlusion reduces epidermal turnover in
`psoriasis. Fry et aI, in 1970,13 suggested that the in(cid:173)
`creased temperature and hydration induced by the
`plastic film could influence the enzymatic processes
`related to keratinization and granular layer formation.
`Friedman6 reported the usefulness of hydrocolloid
`dressings in psoriasis treatment. Hydration induced
`by occlusion may act as a compensating factor in bal(cid:173)
`ancing the damaged water barrier in psoriasis and in
`eliminating the stimulating factor for increased epi(cid:173)
`dermal proliferation.14,15
`The present study has recorded significant differ(cid:173)
`ences in the occlusive potential of the devices inves(cid:173)
`tigated (Figure 2). Hydration, as measured by increased
`water evaporation at the skin surface after removal of
`the device, and water holding capacity of the stratum
`
`Table 1. Water Evaporation After Occlusion
`
`Dressing
`
`1st Minute
`(Mean ± SD)
`
`25th Minute
`(Mean ± SD)
`
`Plastic cham bert
`Hydrocolloid dressing
`Polyethylene film
`Polyurethane film*
`
`1.58 ± 0.37*
`1.44 ± 0.13*
`1.24 ± 0.39*t
`1.00 ± 0.27
`
`0.87 ± 0.12*
`0.78 ± 0.12*
`0.77 ± 0.25*
`0.59 ± 0.11
`
`Comparison of transepidermal water loss values (expressed in log and
`corrected for temperature).
`* Analysis of variance is significant among groups, p < 0.01.
`t Significant differences between subgroups, p < 0.05.
`
`THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES
`
`Table 2. Decay Constants of Evaporation
`
`Dressing
`
`Plastic chamber
`Hydrocolloid dressing
`Polyethylene film
`Polyurethane film*
`
`Mean ± SD
`
`-0.05 ± 0.009*
`-0.045 ± 0.009*
`-0.040 ± 0.025
`-0.028 ± 0.022
`
`Decay constants expressed in log transepidermal water loss.
`Polyurethane film has the lowest decay of evaporation.
`* p < 0.05 vs. the plastic chamber and the hydrocolloid dressing.
`
`corneum reflect different occlusive capabilities of the
`products. Table 1 shows the water evaporation from
`skin surface at the 1st and 25th minutes after the oc(cid:173)
`clusion removal. The sites occluded with the plastic
`chamber and · hydrocolloid dressing give the highest
`scores. Polyethylene film shows values close to the hy(cid:173)
`drocolloid dressing, whereas polyurethane film shows
`lower levels of hydration. The ANOV A is significant
`between the groups (p < 0.01), and the comparison of
`subgroups (Fisher's PLSD test) gives significant dif(cid:173)
`ferences between polyurethane film compared to the
`other dressings at the 1st and 25th minutes. Further(cid:173)
`more, at the 1st minute, immediately after the removal
`of the dressing, the site treated with the plastic chamber
`shows a significantly higher level of hydration com(cid:173)
`pared to the polyethylene occluded site (p < 0.05). Ac(cid:173)
`cordingly (Table 2), the comparison of decay constants
`of water evaporation from skin surface show significant
`differences between polyurethane film vs. the hydro(cid:173)
`colloid dressing and the plastic chamber (p < 0.05).
`These data are consistent with a lower moisturizing
`capacity of polyurethane compared to the other dress(cid:173)
`ings. This may be the result of a reduced occlusive po(cid:173)
`tential of polyurethane, even though factors other than
`simple occlusion may be involved in increasing the hy(cid:173)
`dration and the water holding capacity. Interestingly,
`polyurethane film and the hydrocolloid dressing closely
`adhere to skin surface and stick to it, whereas poly(cid:173)
`ethylene film and the plastic chamber do not touch the
`skin surface and allow water accumulation between the
`plastic edge and the skin.
`The role of hydrocolloid particles in the adsorption
`of moisture from the stratum corneum is unknown. On
`the other hand, from a physiologic point of view, poly(cid:173)
`urethane appears to be the dressing that perturbates
`the skin microenvironment and barrier function the
`least. In the light of this data, this dressing might be
`better tolerated for long-term applications. This study
`attempts to classify and standardize the occlusive po(cid:173)
`tential of dressings commonly used in clinical practice
`to treat skin disorders. The correct ranking of the ef(cid:173)
`ficacy of these products is needed to organize practical
`therapeutic regimens, preventing risks and side effects
`to the patients, especially when occlusion is used to
`enhance skin penetration of potent drugs, such as top-
`
`27
`
`

`

`Occlusion and water Holding Capacity
`
`ical corticosteroids or other compounds with systemic
`effects.
`
`References
`1. Berardesca E, Maibach HI: Skin occlusion: Treatment or drug(cid:173)
`like device? Skin Pharmacoll:207-215, 1988.
`2. Winter GD: Movement of epidermal cells over the wound surface,
`in Montagna W, Billingham RE (eds): Advances in Biology of
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`3. Hinman CD, Maibach H: Effect of air exposure and occlusion
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`4. Alvarez OM, Mertz PM, Eaglstein WH: The effect of occlusive
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`5. Fry L, Almeyda J, McMinn RM: Effect of plastic occlusive
`dressings on psoriatic epidermis. Br J Dermatol82:458-462, 1970.
`6. Friedman SJ: Management of psoriasis vulgaris with a hydro(cid:173)
`colloid occlusive dressing. Arch Dermatol123:1046-1052, 1987.
`7. Rietschel RL: A method to evaluate skin moisturizers in vivo. J
`Invest Dermatol70:152-155, 1978.
`8. Berardesca E, Fideli D, Borroni G, Rabbiosi G, and Maibach H:
`In vivo hydration and stratum corneum water holding capacity
`
`in clinically uninvolved skin in atopies and psoriatics. Acta Derm
`Venereol (Stockh) 70:400-404, 1990.
`9. Mathias T, Wilson D, Maibach H: Transepidermal water loss
`as a function of skin surface temperature. J Invest Dermatol77:
`219-220, 1981.
`10. Wagner J: Linear compartment models: The one compartment
`open model with first order· absorption-single dose, in Wagner
`J (ed): Fundamentals of Clinical Pharmacokinetics. Hamilton,
`Illinois, Drug Intelligence Publications, Inc., 1975, p 74.
`11. Winter GD: Oxygen and epidermal wound healing. Oxygen
`transport to tissue III. Advances in Experimental Medicine and
`Biology 94:673-678, 1977.
`12. Knighton DR, Hunt TK, Scheuenstuhl H, Halliday BJ, Werb
`Z, Banda MJ: Oxygen tension regulates the expression of an(cid:173)
`giogenesis factor by macrophages. Science 221:1283-1285,1983.
`13. Fry L, Almeyda J, Me Minn RM: Effect of plastic occlusive
`dressings on psoriatic epidermis. Br J Dermatol82:458-462, 1970.
`14. Petzold DG, Braun Falco 0, Wenig KH: Effects of plastic foil
`occlusion on psoriatic lesions. Arch Klin Exp Dermatol238:160-
`168,1970.
`15. Marks R: Topical therapy for psoriasis: General principles. Der(cid:173)
`matol Clin 2:383-388, 1984.
`
`The Southern Society for Clinical Investigation has established the Tinsley Harrison Award, given by the
`University of Alabama at Birmingham in memory of Tinsley Randolph Harrison, one of the founders of
`the SSCI.
`The award, given to the author of the best single manuscript published in The American Journal of the Medical
`Sciences during the year, was presented at the recent Southern Clinical Research Meetings
`To: Jeffrey M_ Milunsky
`4th Year Medical Student
`Boston University School of Medicine
`Boston, Massachusetts
`For: "Presymptomatic and Prenatal Diagnosis of Myotonic Muscular Dystrophy"
`
`The Merck, Sharp and Dohme Young Investigator Awards were presented to the following individuals at the
`recent Southern Society for Clinical Investigation Meeting:
`David Calhoun, MD
`Associate Fellow
`University of Alabama at Birmingham
`School of Medicine
`
`"Physical Training Enhances Arterial Baroreflex Control of Heart Rate Sympathetic Nerve Activity"
`
`Scott W. Ebbinghaus, MD
`Research Fellow
`University of Alabama at Birmingham
`School of Medicine
`
`"Triplex Formation Prevents Protein Binding to the HER-2/NEU Promoter"
`
`Daniel Gaitan, MD
`Research Fellow
`Vanderbilt University
`School of Medicine
`
`"Glucocorticoid Receptor Structure and Function in an Ectopic ACTH-Secreting Tumor Cell Line"
`
`28
`
`July 1992 Volume 304 Number 1
`
`