Management of psoriasis vulgaris with a hydrocolloid occlusive dressing

Because clinical improvement of psoriasis vulgaris was recently observed after the prolonged application of tape, 26 patients with symmetric plaque-type psoriasis were enrolled in a prospective bilateral comparison study evaluating the clinical efficacy of the adhesive hydrocolloid occlusive dressing (HCD). The majority of localized plaques of psoriasis achieved improvement (41%, 14/34) or resolution (47%, 16/34) with the prolonged application of HCD; also, HCD was therapeutically superior to twice-daily applications of fluocinolone acetonide cream, and was comparably effective as erythemogenic ultraviolet B treatment. Although the therapeutic mechanism is not completely understood, occlusive dressings have great potential in the management of limited psoriasis vulgaris.     

Skin permeability barrier and occlusion: no delay of repair in irritated human skin *

It has been reported that occlusive treatment of irritated skin results in a reduction of barrier repair activities in hairless mice. In contrast, the clinically observed benefit of occlusion in the treatment of hand eczema and other chronic skin diseases with a perturbed barrier function is well–known. While the beneficial effect of occlusion has been proven for the treatment on psoriasis there are no controlled clinical studies of the effect of occlusion on irritated human skin. We have therefore evaluated the effect of various occlusive treatments on repair of the human skin permeability barrier under controlled experimental conditions. Barrier perturbation was induced either by application of sodium lauryl sulfate (SLS) or by repeated tape stripping. This was followed by treatment with different occlusive and semipermeable dressings, partly alter pre-treatment with petrolatum. Repair of water barrier function was evaluated by daily measurements of transepidermal water loss (TEWL) for 1 week. SLS irritation and tape stripping led to a 6-fold increase in TEWL as a sign of severe water barrier perturbation, followed by a stepwise decrease over the following days. Occlusion did not significantly delay barrier repair as measured by TEWL. Only in tape-stripped skin did TEWL stay at high levels during treatment with self-adhesive dressings. This may be explained by damage of newly formed stratum corneum caused by changing of these membranes. Our results indicate that, in contrast to earlier observations in hairless mouse skin, permeability barrier repair activities are not significantly delayed by occlusive treatment in human skin.     

Occlusive hydrocolloid dressings decrease keratinocyte population growth fraction and clinical scale and skin thickness in active psoriatic plaques.

Clinical studies suggest a therapeutic role for occlusion in the treatment of psoriasis. Previous studies, using multiparameter RNA/DNA flow cytometric analysis of epidermal suspensions obtained from active plaques, demonstrated increased keratinocyte growth fraction which reversed with successful medical treatment. Because keratinocyte growth fraction reflected disease activity, it was used in this study in addition to clinical evaluations in order to determine the efficacy of occlusion in the treatment of psoriatic plaques. In each of 9 patients, scale, skin thickness and erythema were compared in one occluded and one control plaque using an analog scale. Both scale and skin thickness, but not erythema, were decreased after 2 weeks of occlusion. However after 10 weeks, no additional differences were seen when compared with assessments made after 2 weeks, suggesting that the benefits of occlusive therapy occurred early. After 10 weeks of occlusion, the keratinocyte growth fraction was significantly decreased in occluded plaques. This study demonstrates that occlusion plays a synergistic role with other therapeutic modalities in ameliorating psoriatic plaques.     

达力士封包疗法治疗银屑病疗效观察

目的探索达力士软膏封包疗法和常规外用疗法的疗效和安全性。方法用左右肢体对照的方法对55例慢性斑块状银屑病患者采用达力士软膏1次/d封包疗法和2次/d常规外用治疗8周;在治疗后2,4,6,8周根据PASI评估疗效。结果在治疗2,4,6,8周时达力士组PASI评分下降值明显高于常规外用法(t分别=1.7485,2.9561,4.3547,1.88942;P<0.05),达士力组治疗4,6,8周治愈率分别达到26%,58.6%,74%;与常规疗法相比疗效差异显著(χ2=6.45,5.28,5.58,P=0.011,0.021,0.018),达力士组和常规疗法局部刺激发生率分别为15.2%和8.6%,两组疗法都未出现系统不良反应。结论达力士1次/d封包疗法治疗银屑病高效、安全、经济、快速。     

The changes of epidermal calcium gradient and transitional cells after prolonged occlusion following tape stripping in the murine epidermis.

Disruption of the epidermal permeability barrier causes an immediate loss of the calcium gradient, and barrier recovery is parallel with the restoration of the calcium gradient in the epidermis. Artificial restoration of the barrier function by occlusion with a water vapor-impermeable membrane abrogate the expected increase in lipid synthesis and retard the barrier recovery, as well as block the normalization of the epidermal calcium gradient. To clarify the long-term effects of occlusion after acute barrier perturbation, we studied the calcium distribution and epidermal keratinocytes response after occlusion with a water vapor-impermeable membrane immediately following tape stripping in the murine epidermis. Acute barrier disruption caused an immediate depletion of most calcium ions in the upper epidermis, obliterating the normal calcium gradient. When the skin barrier function was artificially corrected by occlusion, the return of calcium ions to the epidermis was blocked. After 2 h of air exposure or occlusion, the density of epidermal calcium precipitates remained negligible. The transitional cell layers appeared with occlusion, but not or negligibly with air exposure. By 6 h though, calcium precipitates could be seen, the density of the calcium precipitates with occlusion was more sparse than with air exposure. With the air exposure, the thickness of the stratum corneum had normalized and the calcium gradient nearly recovered to normal after 24 h. The longer the occlusion period, the greater was the increase of transitional cells. By 60 h of occlusion, the thickness of the stratum corneum had increased and the transitional cell layers had disappeared, in parallel with the calcium gradient which was almost normalized. These results show that prolonged occlusion of tape-stripped epidermis induced transitional cells and delayed the restoration of the epidermal calcium gradient, the stratum corneum was then restored, transitional cells having disappeared, in parallel with normalization of the epidermal calcium gradient.     

The psoriasis area and severity index is the adequate criterion to define severity in chronic plaque-type psoriasis

BACKGROUND: Chronic plaque-type psoriasis is a major dermatosis, but a significant question is still unanswered: What defines severity in chronic plaque-type psoriasis? While objective assessments like the Psoriasis Area and Severity Index (PASI) have frequently been used in clinical trials, quality of life (QOL) questionnaires are currently becoming more and more popular. OBJECTIVE: This article summarizes the most important objective and subjective measurements of severity in psoriasis. For every dermatologist it is critically important to distinguish between severe psoriasis and psoriasis that severely affects QOL. Even if the PASI also has disadvantages, it is the most adequate instrument available to evaluate severity in plaque-type psoriasis. RESULT: We provide reasons why PASI >12 defines severe, PASI 7-12 moderate and PASI <7 mild chronic plaque-type psoriasis.     

Increased permeability of psoriatic skin to the protein,plasminogen activator inhibitor 2

The penetration and permeation of the recombinant protein plasminogen activator inhibitor type 2 (PAI-2) in two formulations, one containing a penetration enhancer, into the psoriatic and uninvolved skin of eight patients with plaque-type psoriasis were investigated. Penetration and permeation of PAI-2 were measured by gamma counting and imaging following radiolabelling of a fraction of the applied PAI-2 with ¹²³I. The feasibility of topical delivery of drug to psoriatic plaques was confirmed by the finding that the permeability of psoriatic plaques to radiolabelled PAI-2 (P=0.007) and free ¹²³I (P=0.001) was approximately tenfold higher than the permeability of uninvolved skin. The addition of a penetration enhancer improved the permeation of PAI-2 into psoriatic plaques from an average of 35% to 46% (P=0.005). Occlusion decreased the permeation amount of PAI-2 from 46% to 15% due to losses on the occlusive dressing (P=0.001).Abbreviations PA Plasminogen activator - PAI-2 Plasminogen activator inhibitor, type 2 - tPA Tissue plasminogen activator - uPA Urinary plasminogen activator     

Tacrolimus ointment improves psoriasis in a microplaque assay

Tacrolimus (FK506) is an effective and well tolerated immunosuppressant used to prevent allograft rejection. We describe the evaluation of two tacrolimus ointment formulations for treatment of chronic plaque-type psoriasis. This was a microplaque assay with randomized, double-blind design. Sixteen patients (15 men, one woman, all white and 28-69 years old) with chronic plaque-type psoriasis participated. Six different ointments were applied to discrete microplaques, 17 mm in diameter, on a descaled psoriasis lesion: these were tacrolimus ointment with diisopropyl adipate as penetration enhancer, tacrolimus ointment without diisopropyl adipate, 0.1% betamethasone 17alpha-valerate ointment, 0.005% calcipotriol ointment and, as controls, the ointment bases for tacrolimus and betamethasone. Ointments were reapplied and the area was sealed every 2-3 days during the 14-day treatment period. After 7 and 14 days, erythema and infiltration were graded on a scale of 0-4, and superficial blood flow was measured with a laser Doppler flowmeter. Epidermal thickness was measured histologically at the end of treatment. Compared with the vehicle controls, sites treated with tacrolimus ointment (with or without penetration enhancer) showed a significant reduction in erythema and infiltration (P < 0. 001), a significant reduction in superficial blood flow (P < 0.01) and a significant decrease in epidermal thickness (P < or = 0.001). Results for betamethasone and calcipotriol, when compared with the vehicle controls, were similar. These results suggest that, under conditions of descaling and occlusion, tacrolimus ointment is effective in the treatment of psoriasis.     

Integrity of the permeability barrier is crucial for maintenance of the epidermal calcium gradient

Summary Prior studies have demonstrated a Ca²⁺ gradient within the epidermis, with the highest concentration in the outer nucleated layers, disappearance of the Ca²⁺ gradient when the permeability barrier is acutely disrupted, and reappearance of the Ca²⁺ gradient in parallel with barrier repair, and disruption of the gradient in psoriasis. These observations suggest that integrity of the permeability barrier may maintain the epidermal Ca²⁺ gradient. To determine further whether a functional barrier is crucial for maintaining the Ca²⁺ gradient, we examined Ca²⁺ distribution by ion-capture cytochemistry in essential-fatty-acid-deficient (EFAD) and topical-lovastatin-treated mice, which display a chronic barrier abnormality. In both models, loss of the Ca²⁺ gradient occurred due to increased cytosolic Ca²⁺ in the lower epidermis, which normally displays a paucity of Ca²⁺. Moreover, artificial barrier restoration for 48 h with a water vapour-impermeable wrap normalized the Ca²⁺distribution pattern. Acute barrier disruption also leads to the loss of the Ca²⁺ gradient, but in contrast with the chronic models, loss of the gradient was due to decreased Ca²⁺ in the upper epidermis. Occlusion with a vapour-impermeable wrap blocked restoration of the Ca²⁺ gradient after acute barrier disruption. These results demonstrate that chronic barrier disruption increases Ca²⁺ in the epidermis, and blockade of water flux normalizes Ca²⁺ distribution, whereas acute barrier disruption leads to loss of Ca²⁺, and blockade of water flux prevents the return of Ca²⁺. We conclude: (i) that the epidermal Ca²⁺ reservoir is derived from the movement of fluids and Ca²⁺ across the basement membrane, and (ii) that the integrity of the permeability barrier maintains the epidermal Ca²⁺gradient.     

Therapeutic response to a dermatologic patch and betamethasone valerate 0.1 percent cream in the management of chronic plaques in psoriasis

The efficacy of a hydrocolloid dermatologic patch (Actiderm) in conjunction with topical beta-methasone valerate 0.1 percent cream was studied in outpatients with chronic plaque-type psoriasis treated for three weeks, and observed for an additional two weeks after therapy. A significant degree (p less than 0.05) of lesion resolution occurred at the site treated with the dermatologic patch plus steroid cream, whereas sites treated with either agent alone showed mild but insignificant change. It was concluded that the patch was a highly effective adjunct in the treatment of chronic plaques of psoriasis.     

Origin of the epidermal calcium gradient: regulation by barrier status and role of active vs passive mechanisms

Mammalian epidermis displays a characteristic calcium gradient, with low calcium levels in the lower, basal, and spinous epidermal layers, whereas calcium levels increase progressively towards the outer stratum granulosum, and declining again in the stratum corneum. As the calcium gradient disappears after acute permeability barrier disruption, and returns after 6 h in parallel with barrier recovery, barrier function (through restriction of transcutaneous water movement) could regulate the formation of the epidermal calcium gradient. Two types of experiments confirmed the role of barrier status in regulating the calcium gradient: (i) either a vapor-permeable membrane (Gore-Tex) or an emollient (Vaseline), applied after acute barrier disruption, immediately restored barrier function, while accelerating the return of the calcium gradient, and (ii) in contrast, applications of lovastatin, a cholesterol synthesis inhibitor, which delayed barrier recovery and retarded the return of the calcium gradient. We next asked whether the calcium gradient is formed/maintained by passive and/or active mechanisms. Previous studies have demonstrated that cold exposure (4 degrees C) blocks permeability barrier recovery after acute disruption. Here, we abrogated the barrier with tape-stripping, and then compared barrier recovery and restoration of the calcium gradient in hairless mice exposed to 4 degrees C external temperatures, with and without occlusion with Gore-Tex. Although low levels of returned calcium throughout the epidermis, acutely disrupted, unoccluded, cold-exposed sites showed neither barrier recovery nor reappearance of the calcium gradient at 5 h. In contrast, acutely disrupted, cold-exposed sites, covered with Gore-Tex, likewise displayed little barrier recovery, but the calcium gradient largely returned by 3 h. These results show that (i) barrier status regulates formation of the calcium gradient, and (ii) passive processes alone can account for the formation/maintenance of the calcium gradient.     

Action of topically applied arachidonic acid on the skin of patients with psoriasis

Concentrations of arachidonic acid ranging from 0.1% to 2% were applied under occlusive dressings to psoriatic plaques in 45 patients. Alleviation of the clinical symptoms of psoriasis including complete clearing in some cases was obtained with the use of 0.5% to 2% arachidonic acid applied under occlusion every 24 to 48 hours five to seven times. Histologic examination showed polymorphonuclear leukocytes penetrating into the stratum corneum and formation of microabscesses or wide-spread accumulations of polymorphonuclear leukocytes in the stratum corneum, with its eventual destruction. The parakeratotic horny layer became detached; this was followed by restoration of the granular layer and an apparently normal stratum corneum. While arachidonic acid metabolites can be proinflammatory and proproliferative, they may also be important in the healing process for psoriasis.     

Antipsoriatic effect of local corticosteroids—O2-consumption and blood flow measurements compared to clinical parameters

Ten patients with chronic plaque-type psoriasis were treated topically with the group IV corticosteroid clobetasol propionate cream (Dermovate) with and without occlusion with a semipermeable hydrocolloid dressing (Comfeel Coloplast, Denmark). The effect of treatment was compared with untreated skin and evaluated in terms of (a) O2-consumption as measured by the TCM-2-oxygen monitor from Radiometer, Denmark, (b) blood flow as measured by a laser-Doppler flowmeter (Perimed, Sweden), (c) temperature measurements using thermo-couples and (d) a clinical score. While steroid + occlusion had a very pronounced effect measured by all parameters and apparent after 24 h, the steroid alone was only marginally effective after 7 days. No placebo effect was detectable in untreated skin with the laboratory methods used. It is suggested that the methods described can be used to evaluate other treatment schedules. Recently it has been shown that measurement of oxygen consumption by transcutaneous O2 electrodes might reflect disease activity in psoriatic plaques. Transcutaneous O2 decreases when a tourniquet is applied around the extremity investigated and the decrease per minute has been used as a measure of the metabolism of normal and psoriatic skin. In a later study it was shown that stripping of the skin prior to measuring was essential as a diffusion barrier was present in the horny layer. It has been previously shown that occlusion of an area to which corticosteroid has been applied increases absorption as estimated by the intensity of blanching. In the present study the effect of occlusion and non-occlusion of corticosteroid treated sites in psoriasis has been compared using clinical and laboratory parameters.     

Effectiveness and usability of short-time treatment of psoriasis vulgaris with two different corticosteroids under occlusion with a hydrocolloid dressing (ContreetR)

Objectives To evaluate the efficacy of treatment of plaque-type psoriasis with a moderate and a strong corticosteroid under continuous hydrocolloid occlusion, with weekly change of dressing, compared with treatment with the same corticosteroids alone, and the acceptance by the patients of his type of treatment. Setting Dermatological Departments of two University Hospitals and four General Hospitals. Design Open parallel study divided in two parts depending on the two different corticosteroid preparations applied. Each part was an intrasubject half-side study with left-right comparison. Subjects Fifty five patients with symmetrical, stable psoriasis plaques on elbows or knees. Methods Twenty nine patients were treated with clobetason butyrate cream (Emovatc^R) twice daily as well as once weekly covered with a hydrocolloid dressing (Contreet^R) for four weeks. Twenty six patients were treated with clobetasol propionate cream (Dermovate^R) twice daily as well as once weekly covered by the hydrocolloid dressing for 2 weeks. Induration, erythema and scaling were assessed using a four-point scale. Plaque size was measured by multiplying the largest and the smallest diameter. Healing was defined as score 0 for scaling and induration and score 0 or 1 for erythema. Acceptance was evaluated by questions related to the wearing of the dressings: comfort of wearing, pain, itching, adhesiveness and sticking to clothing, and the performance of daily activities. Statistics analysis Sign test for the score values, parametric paired Student t-test for plaque size, chi-square test for healing. Results With occlusion a statistically significant increased reduction of severity was obtained compared to treatment without occlusion; this effect was more pronounced with the application of the strong corticosteroid. The questions related to the wearing of the dressing were answered positively by the majority of the patients. Conclusions Treatment of psoriasis plaques with, especially strong, corticosteroid creams under occlusion with a hydrocolloid dressing with a high adherence is rapid and effective. The acceptance of this type of treatment by the patients is high, and it permits normal daily activities.     

An experimental ointment formulation of pimecrolimus is effective in psoriasis without occlusion

Pimecrolimus (Elidel, SDZ ASM 981), a new macrolactam ascomycin derivative, was highly effective in treating plaque-type psoriasis when applied under Finn-chamber occlusion. A two-centre, randomized, double-blind, vehicle- and positive-controlled within-patient study was therefore conducted in 23 adult psoriasis patients. Pimecrolimus 1% was applied, twice daily, in an experimental ointment formulation, along with the corresponding vehicle, 0.005% calcipotriol ointment and 0.05% clobetasol-17-propionate ointment to test sites without occlusion for 21 days. Erythema, induration and scaling (score: 0 [absent] to 4 [severe]) were evaluated. The total sign score was defined as the sum of the erythema, induration and scaling scores (range 0-12). Pimecrolimus 1% ointment was significantly (p = 0.03) more effective than the corresponding vehicle, with an improvement in total sign score of 51.4% compared with 36.7% for the corresponding vehicle. Improvements with calcipotriol and clobetasol-17-propionate were 71.5% and 88.3%, respectively. No local or systemic drug-related side effects were observed in the study. We conclude that pimecrolimus 1% in the experimental ointment formulation was significantly more effective than its corresponding vehicle, but less effective than calcipotriol and clobetasol ointment. This is the first study reporting a significant therapeutic effect of pimecrolimus in an ointment formulation applied without occlusion to psoriatic plaques.     

Disappointing results and low tolerability of photodynamic therapy with topical 5-aminolaevulinic acid in psoriasis. A randomized, double-blind phase I/II study

BACKGROUND: Based on good results in the treatment of superficial skin tumours, since the early 1990s topical photodynamic therapy with aminolaevulinic acid (ALA PDT) has been used for disseminated, inflammatory dermatoses including psoriasis. However, there is still a lack of well-documented trials. OBJECTIVE: A prospective randomized, double-blind phase I/II intrapatient comparison study was conducted in 12 patients to investigate whether topical ALA PDT is an effective treatment for chronic plaque-type psoriasis. METHODS: In each patient three psoriatic plaques were randomly treated with a light dose of 20 J/cm(2) and 0.1%, 1% and 5% ALA, respectively. Treatment was conducted twice a week until complete clearance or for a maximum of 12 irradiations. Therapeutic efficacy was assessed by weekly determination of the psoriasis severity index (PSI). RESULTS: The mean percentage improvement was 37.5%, 45.6% and 51.2% in the 0.1%, 1% and 5% ALA-treated groups, respectively. Irradiation had to be interrupted several times because of severe burning and pain sensation. CONCLUSION: Topical ALA PDT did not prove to be an appropriate treatment option for plaque-type psoriasis due to disappointing clinical efficacy, the time-consuming treatment procedure and its unfavourable adverse event profile.     

Barrier repair in chronic plaque-type psoriasis

Purpose: To investigate barrier repair after mild trauma in lesional skin of psoriasis patients with chronic plaque-type disease and to compare this with non-involved psoriatic skin and normal controls.
Methods: Transepidermal water loss (TEWL) readings were taken from involved psoriatic skin and non-involved skin of psoriasis patients as well as the skin of normal controls. Three readings were performed at each site: the basal state, immediately after 20 tape strippings and 1 week post stripping.
Results: Higher baseline, post-stripping and 1-week recovery TEWL readings in psoriatic-involved skin compared to non-involved and normal control skin. No significant difference in barrier recovery rate in psoriatic-involved skin compared to non-involved and normal control.
Conclusion: Although there appears to be a derangement of barrier function in lesional skin of psoriasis patients compared to non-lesional skin and the skin of healthy controls, the barrier recovery function of lesional psoriatic skin is still fully operational.     

Primary annular plaque-type psoriasis

We described two adolescent girls with untreated, consistently annular, plaque-type psoriasis without pustules, a presentation that is to our knowledge, not previously described. No typical confluent plaque-type lesions were present. The plaques in our patients resembled other entities such as tinea corporis and erythema annulare centrifugum, given the erythematous, scaling borders and central clearing. Biopsy specimens from our patients showed features characteristic of psoriasis vulgaris. Both patients responded to combination therapy with calcipotriene and a mid-potency steroid. We conclude that primary annular plaque-type psoriasis shares features of both typical plaque-type and annular pustular psoriasis, suggesting that these entities represent a spectrum of psoriatic disease.     

Programmed cell death of keratinocytes in infliximab-treated plaque-type psoriasis

BACKGROUND: Tumour necrosis factor (TNF)-alpha blockade using infliximab, a chimeric anti-TNF-alpha antibody, is an effective treatment for plaque-type psoriasis, inducing remission in about 80% of patients. OBJECTIVES: To examine infliximab-induced programmed cell death (PCD) of keratinocytes in psoriatic plaques on serial skin biopsy samples. METHODS: Five patients with moderate to severe plaque-type psoriasis received infliximab infusions intravenously (5 mg kg(-1)) at weeks 0, 2 and 6. Biopsies of nonlesional and lesional skin (days 0, 5, 14 and 21) were obtained. Conventional microscopy was used to examine the morphology of the psoriatic keratinocytes. In situ detection of apoptosis was performed by electron microscopy and by immunohistochemical staining with anti-p53 and anti-caspase-3 antibodies. Results Infusion of infliximab induced a clinical response in all five patients with psoriasis, with a mean Psoriasis Area and Severity Index improvement of 24.8% already at day 5. This was accompanied by significant histopathological changes in the skin biopsy samples after infliximab treatment. Light and electron microscopic evaluation revealed apoptosis-like morphological changes in lesional keratinocytes, i.e. nuclear condensation, chromatin fragmentation and cytoplasmic vesiculation, visible already after the first infusion. These damaged keratinocytes stained positively for p53, but not for active caspase-3. CONCLUSIONS: The effects of infliximab in psoriasis extend beyond merely anti-inflammatory actions, and may include caspase-independent PCD of lesional keratinocytes. The PCD of keratinocytes may be an important mechanism that could explain at least in part the rapid and sustained therapeutic effect of infliximab in psoriasis.     

Skin barrier response to occlusion of healthy and irritated skin: Differences in trans‐epidermal water loss,erythema and stratum corneum lipids

Background. Occlusion of the skin is a risk factor for development of irritant contact dermatitis. Occlusion may, however, have a positive effect on skin healing. No consensus on the effect of occlusion has been reached. Objectives. To investigate skin barrier response to occlusion on intact and damaged skin. Methods. In study A, the response to occlusion (nitrile glove material) for either 8 hr daily for 7 days or for 72 consecutive hours, respectively, was determined and compared with that of non‐occluded skin. In study B, the response to occlusion of for 72 consecutive hours of skin that had been damaged by either sodium lauryl sulfate (SLS) or tape stripping, respectively, was determined and compared with that of to non‐occluded pre‐damaged skin. Skin barrier function was assessed by measurements of trans‐epidermal water loss (TEWL) and erythema. In study A, stratum corneum lipids were analysed. Results. Occlusion of healthy skin did not significantly influence skin barrier function, ceramide profile or the ceramide/cholesterol ratio. Occlusion of the skin after SLS irritation resulted in higher TEWL than in the control (P = 0.049). Occlusion of the skin after tape stripping resulted in lower TEWL than in control skin (P = 0.007). Conclusions. A week of occlusion did not significantly affect healthy skin, but was found to decrease healing of SLS‐damaged skin, and to improve healing of tape‐stripped skin.