Can Skin Moisturizers Prevent Irritant Contact Dermatitis?

BULLETIN FOR MEDICAL PRACTITIONERS

Professor Goh Chee Leok
Senior Consultant and Medical Director
National Skin Centre

Introduction

Moisturizers are probably the most used skin care products. Moisturizers are applied to the hands, face and other parts of the body daily for preventing and treating dry skin and irritant contact dermatitis. Cumulative insult dermatitis resulting from
repetitive stratum corneum injury leads to chronic dermatitis which presents as dry scaly skin. These changes are preceded subclinically by changes in skin physiological functions e.g. decreased capacitance, increased transepidermal water loss (TEWL) and increased blood flow that can be measured with various devices(1).

The application of moisturizers has been shown in several studies to be effective in the prevention of irritant contact dermatitis. It is an important preventive measure where the wearing of gloves is not possible or inappropriate. Moisturizers have been reported to reinforce the natural barrier function of the skin by increasing the water content of the stratum corneum. Studies have shown that eczematous skin heals faster when treated with a moisturizer compared to untreated, symmetrical, control skin. This article reviews reports on the efficacy of moisturizers in preventing irritant contact dermatitis.

How do moisturizers work?

The contents of a typical moisturizer includes lipids, humectants, emulsifiers, preservatives, pH-adjusters and fragrances. The important role of lipids in skin moisturization has been demonstrated in studies which shows that lipid removal by acetone or ether leads to dry, scaly skin and removal of intercellular lamellae bodies. Topical application of strateum corneum lipids leads to moisturization and ceramide creams lead to significant improvement in dry skin. Comparisons of different moisturizers on sodium lauryl sulfate (SLS)-irritated skin demonstrate that the efficacy is related more to the total
amount of lipids rather than to the composition of lipids(2,3,4).

Imokawa using forearm stratum corneum sheets compared the ultrastructural changes of intercellular lipids and showed that stratum corneum lipids serve as a bound-water modulator(2,3,4). Extraction of the stratum corneum sheet with acetone/ether decreased the bound-water content from 33.3% to 19.7% leading to dry and scaly skin. Further extraction with water, which released water-soluble materials e.g. amino acids, did not change the bound-water content. Electron microscopy analysis of the acetone/ether treated stratum corneum sheet revealed selective depletion of lipids from intercellular spaces,
accompanied by marked disruption of lamellar structures.

Application of the stratum corneum lipids solubilized in squalane containing 1% alpha-monomethyl-heptadecyl glyceryl ether to lipid-depleted stratum corneum sheet caused a significant recovery of bound-water content to the previous, almost normal level and a significant improvement in dry skin. In addition, the application of the lipids onto the lipid-depleted stratum corneum sheet resulted in restoration of the lamellar structures(2,3,4). These findings strongly suggest that stratum corneum
lipids serve a water-holding function through formation of lamellar structures within the stratum corneum.

Does diseased skin heal faster when a moisturizer is applied and does daily use of moisturizers on normal skin improves barrier function?

Objective non-invasive assessment of dry skin includes measurements of skin conductance, impedance, capacitance(corneometer) and roughness (profilometry). The damage of the stratum corneum leading to its loss of
water retention property can be measured by TEWL measurements(5,6).

Hannuksela et al(7) studied the ability of 8 moisturizers to prevent ICD. 12 students washed their upper arms with liquid detergent for 1 minute 2 times a day for 1 week. Seven different creams and one oil were applied to the left upper arm after each washing on volunteers, while the right upper arm was left untreated. The mean TEWL increased from 7.1 to 9.3 g/m /h (p<0.001) and mean laser Doppler flowmetry value decreased from 11.8 to 10.8 units (n.s.) on the left arm but increased from
7 to 20 g/m /h and 11 to 20 units on the right arm. During the second week of their study, the volunteers stopped washing their arms. The untreated right arm was treated with moisturizers 2 times a day. The mean TEWL decreased from 20.3 to 8.6 (p<0.001) over 7 days. Laser Doppler flowmetry values showed the same trend as TEWL. It thus appears that the regular use of emollients can prevent irritant dermatitis from a detergent.

Loden(8,9) reported that a urea-containing moisturizer speeds up healing and decreases susceptibility to SLS. In a single-blind study, a moisturizing cream was tested for its influence on barrier recovery in surfactant-damaged skin and the susceptibility of normal skin to SLS. TEWL and skin capacitance were measured. The authors found that barrier recovery and influence of irritant stimuli on skin treated with a moisturizing cream was more favorable then untreated skin. Treatment of surfactant-damaged skin with the test cream for 14 days promoted barrier recovery that was observed as a decrease in TEWL. Skin capacitance also normalized more rapidly during

treatment. In normal skin, the use of the moisturizing cream significantly reduced TEWL after 14 days of treatment, and
irritant reactions to SLS were significantly reduced. Skin capacitance increased after only 1 application and remained elevated after 14 days. The authors concluded that, the accelerated rate of recovery of surfactant-damaged skin and the lower degree of SLS-induced irritation in normal skin treated with the moisturizing cream might be of clinical relevance in attempts to reduce irritant contact dermatitis.

There were other reports that further support the role of moisturizers in preventing irritant contact dermatitis. Ramsing and Agner in 1997 showed using the hand immersion test that moisturizer tested on experimentally irritated skin of 12 volunteers prevents SLS irritation and sped up healing of irritation(13). The volunteers had both hands immersed into 0.375% SLS solution for 10 minutes 2 times a daily for 2 days. Before immersion, one hand was treated with a moisturizer; other hand served as control. Skin barrier functions were evaluated by TEWL, LDF and capacitance. The 12 volunteers had both hands immersed in the same way. After the last immersion, one hand was treated for 5 days with the moisturizer; the other hand served as control. There was a significant preventive effect on the treated hand, compared to the control hand by all measured parameters. Skin barrier function and skin hydration on treated hand was better than control hand.

Protective gloves are used in the workplace to protect hands from occupational hazards, but side effects from gloves are frequently reported. Amongst these side effects include irritant skin reactions. Held et al(10) studied the combined use of moisturizers and occlusive gloves. The study investigated whether applying a moisturizer to compromised skin before wearing an occlusive glove could reduce skin irritation. Healthy volunteers had both hands immersed in SLS 2 times daily for 2 days. After each immersion, one hand had a moisturizer applied and both hands put on occlusive gloves for 2 hours. Skin barrier function was evaluated by TEWL, skin capacitance and inflammation evaluated by colorimetry. The moisturizer had a statistically significant positive effect on water barrier function and hydration. Less inflammation was observed on moisturizer-treated hand. Their findings suggest that the use of moisturizer under occlusion may diminish irritation from detergent.

Clinical studies on the efficacy of moisturizers in preventing irritant contact dermatitis

There are few controlled prospective intervention field studies on moisturizers against irritant contact dermatitis. Halkier-Sorensen & Thestrup-Pedersen in 1993 reported that moisturizers reduce dryness in cleaners and kitchen assistants during exposure to water and detergents(11). The efficacy of moisturizers among cleaners and kitchen assistants during everyday exposure to water and detergents was studied. 55 volunteers used moisturizers for 2 weeks (period L), followed by a period without (period C), or vice versa. Assessment and measurements of the skin surface temperature, electrical capacitance and TEWL were performed on the fingers, hands and arms on entry to the study, after 2 weeks and 4 weeks, or at drop out. A significant increase in dryness (p < 0.001) during periods of no treatment (period C), and normalization of the skin texture during use of moisturizer. Electrical capacitance, decreased during period C, increased to pre-study values during period L (p < 0.001). The authors reported that moisturizers had a positive effect in preventing skin irritation.

Goh et al(12) showed that an after-work moisturizer appeared to reduce the incidence of irritant dermatitis, and prevent TEWL increase from cutting oil among metal workers(8). Point prevalence of cutting fluid dermatitis according to the severity and TEWL changes over a 30-week study period showed a lower incidence of irritant contact dermatitis and lower TEWL increase in workers who used after-work moisturizers compared to those who do not and those using only barrier creams.

In another field study, Perrenoud et al(13) compared the protective action of a new barrier cream to its vehicle, in hand irritation of apprentice hairdressers caused by repeated shampooing and exposure to hair-care products. 21 apprentice hairdressers (20 female, 1 male) who were starting their 2nd year of studies were recruited. A double-blind cross-over comparing Excipial Protect (the verum, containing aluminum chlorohydrate 5% as active ingredient) against its vehicle alone (the control). Measurements were taken on Monday at the end of their 2-day weekly break and again on Friday (the next-to-last day of their work-week). Additionally, the back of the dominant hand was clinically evaluated for dryness, redness, and breaks in the skin. At the end of the study period, the clinical scores were generally very low: nearly everyone replied 0 (none) or 1 (mild) under either cream and there was clearly no difference between the treatments. Only corneometric values showed a difference between the verum and the control. The averages for corneometry were significantly higher in the control period than the verum period (p<0.01). Evaporimeter values increased under verum treatment, without reaching statistical significance. In the control periods, the mean corneometric values were higher than in the verum periods. This suggests that the control cream is more hydrating than the verum cream. It appeared that the base cream vehicle alone in the prevention of occupational irritant contact dermatitis is important in preventing irritant contact dermatitis.

In contrast to most reports, Held et al in 1999 reported that moisturizers which improves stratum corneum hydration may increased skin susceptibility to contact irritants. In her studies, a 4-week treatment of normal skin with moisturizer increases susceptibility to SLS(14,15). Paradoxically, excessive hydration of the normal stratum corneum may reduce its barrier efficiency. This hypothesis was investigated in 20 volunteers with normal skin(19,20). Held et al applied a moisturizer (with 70% lipid) 3 times a day for 27 days on 1 forearm of 20 volunteers. The other untreated forearm acted as control. On day 28 (after stopping moisturizer), an irritant skin reaction was elicited on each volar forearm with a patch test of SLS for 24 h. On day 30, a statistically significant higher TEWL was found on the SLS-irritated area in moisturizer-treated arms compared to their untreated symmetrical controls. The results suggest that long-term treatment with moisturizers on normal skin may not necessarily offer any protection against irritant trauma caused by a detergent.

On the contrary, daily use of moisturizers under these conditions may increase skin susceptibility to irritants. When the stratum corneum is overly hydrated it may become more permeable to hydrophilic substances such as SLS.

Conclusion

From the reported articles, it appears that moisturizers do confer some “protective” effects against skin irritants. However, in most of these reports, single product was tested to a single irritant. The protective effects of moisturizers may not be “broad spectrum”. Some reports appear to indicate that overuse of moisturizers may have harmful effects when used on normal skin. Obviously, more clinical studies on this topic need to be carried out to further elucidate the efficacy of moisturizers against
irritant contact dermatitis and controlling xerosis.

Finally, moisturizers are not totally without side-effects. Workers using moisturizers must be aware that it may cause skin irritation and sensitization. Sensitizers in moisturizers include fragrances, preservatives, emulsifiers and humectants.

References

1. Barany-E, Lindberg-M, Loden-M. Biophysical characterization of skin damage and recovery after exposure to different surfactants. Contact-Dermatitis 1999; 40: 98-103.
2. Imokawa-G, Akasaki-S; Hattori-M, Yoshizuka-N. Selective recovery of deranged water-holding properties by stratum corneum lipids. J-Invest-Dermatol 1986; 87: 758-61.
3. Imokawa-G, Akasaki-S; Minematsu-Y, Kawai-M. Importance of intercellular lipids in water-retention properties of the stratum corneum: induction and recovery study of surfactant dry skin. Arch-Dermatol-Res 1989; 281: 45-51. 
4. Imokawa-G, Kuno-H, Kawai-M. Stratum corneum lipids serve as a bound-water modulator. J-Invest-Dermatol 1991; 96: 845-51.
5. Serup-J, Winther-A, Blichmann-C. A simple method for the study of scale pattern and effects of a moisturizer—qualitative and quantitative evaluation by D-Squame tape compared with parameters of epidermal hydration. Clin-Exp-Dermatol 1989; 14: 277-82.
6. de-Fine-Olivarius-F, Hansen-AB, Karlsmark-T, Wulf-HC. Water protective effect of barrier creams and moisturizing creams: a new in-vivo test method. Contact Dermatitis 1996; 35: 219-25.
7. Hannuksela A, Kinnumen T. Moisturizers prevent irritant dermatitis. Acta-Derm-Venereol 1992; 72: 42-4.
8. Loden-M. Urea-containing moisturizers influence barrier properties of normal skin. Arch-Dermatol-Res 1996; 288:103-7.
9. Loden M. Barrier recovery and influence of irritant stimuli in skin treated with a moisturizing cream. Contact-Dermatitis 1997; 36: 256-60.
10. Held-E, Jorgensen-LL. The combined use of moisturizers and occlusive gloves: an experimental study. Am-J-Contact-Derm 1999; 10: 146-52
11. Halkier-Sorensen-L, Thestrup-Pedersen-K. The efficacy of a moisturizer (Locobase) among cleaners and kitchen assistants during everyday exposure to water and detergents. Contact Dermatitis. 1993; 29: 266-71.
12. Goh CL, Gan SL. Efficacies of a barrier cream and an afterwork emollient cream against cutting fluid dermatitis in metalworkers: a prospective study. Contact Dermatitis. 1994;31:176-80.
13. D Perrenoud, D Gallezot, G van Melle. The efficacy of a protective cream in a real-world apprentice hairdresserenvironment. Contact Dermatitis 2001:45; 134-8.
14. Held E, Sveinsdottir S, Agner T. Effect of long-term use of moisturizer on skin hydration, barrier function and susceptibility to irritants. Acta Derm Venereol 1999;79:49-51.
15. Held E. So moisturizers may cause trouble! Int J Dermatol 2001;40:12-3.
     

DEDICATED TO EXCELLENCE IN DERMATOLOGY
By National Skin Centre (Singapore)
Copyright (C) 1995 - National Skin Centre (Singapore)

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