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It is an often-overlooked fact that all occlusive gloves such as those worn as protection against chemical hazards can cause damage to the skin regardless of the material they are manufactured from. This article will explain why and how this needs to be incorporated into our approach to the selection and use of gloves for chemical protection.
In order to appreciate why and how this skin damage occurs, we need first to understand some basic facts about our skin and how it works. The following is a very simple description of how our skin is formed of two main layers, the dermis and the outer layer, the epidermis.
Understanding the skin
The dermis is where the main strength and elasticity of the skin is to be found. It is in the epidermis that we find the barrier function of the skin. As the diagram shows, the epidermis can be itself be divided into two main layers. The lower layer, sometimes referred to as the ‘viable epidermis’ is comprised of living cells, the most common of which is the keratinocyte. These are formed by cells in the lowest part of this layer duplicating themselves. One cell then migrates outwards, undergoing several changes on the way. Eventually it loses its living nucleus and is filled with a hard protein (keratin) and becomes a flattened, inert cell, now called a corneocyte. Layers of corneocytes form an outermost layer, the stratum corneum. Eventually corneocytes are shed from the surface. We can lose around one million corneocytes every 24 hours. They are too small to be seen by the naked eye. Over most of our body the whole epidermis is no more than 0.1-0.2.mm thick. The stratum corneum is around 0.01-0.02mm thick and it is this layer that provides the barrier that keeps us alive.
The stratum corneum also provides the barrier that prevents our body from losing excessive amount of water. Within the stratum corneum are two microscopically thin layers of lipids. The bottom layer allows a controlled amount of water to pass through into the stratum corneum. This is needed for the corneocytes to function properly. If we were simply to allow this to evaporate from the surface our skin would very quickly become very dry and brittle and cease to function. The outermost layer is an emulsion that limits the rate at which this moisture can evaporate from the surface. It thus helps to maintain the moisture level in the stratum corneum needed for this to function properly.
We thus lose water through our skin continuously without being aware of this. We call this trans-epidermal water loss (TEWL).
The average person will lose between 480 and 1100 g of water each day, of which 65% (300-700 g) will be lost through the skin and 35% through respiration. From “On the measurement of evaporative water loss, Nilsson G.E., Linköping Studies in Science and Technology Dissertations, No. 11, 1977)
As a major concern will be to maintain the barrier properties of our skin anything that has an adverse effect on this should be avoided where possible. One problem is that any irritant damage to the skin’s barrier will accumulate asymptomatically, i.e. there will be no visual or sensory awareness that this is happening. Ultimately the point is reached where the damage does become visible, but long before this the skin is more easily colonised by transient, potentially infective, micro-organisms. (Note that there are measurement techniques that can detect this asymptomatic damage.)
In addition to TEWL we can also lose moisture through sweat glands. The primary function of the sweat gland moisture is to evaporate thereby removing excess heat from the body.
“with good quality gloves allergic reactions are relatively uncommon, what is much more common is the irritant reaction due to the effect of occlusion”
Gloves as a hazard to health
The opening statement was that all occlusive gloves present a hazard to the skin regardless of the material they are made from. However, all to often when the damage becomes apparent the assumption is made that this is an allergic reaction to some chemical in the glove. The reality is that, with certain exceptions, with good quality gloves allergic reactions are relatively uncommon. What is much more common is the irritant reaction due to the effect of occlusion.
An allergic skin reaction requires that the acquired immune system develops antibodies that can recognise a particular chemical such that an allergic reaction may occur. This process, known as sensitisation, is a precursor to an allergic reaction and is asymptomatic. Once sensitisation has occurred a subsequent presence in the skin of that particular chemical may cause a strong reaction of the immune system initiating a condition known either as allergic contact dermatitis or allergic contact urticaria. This is substance specific so avoidance of that substance will almost always eliminate the possibility of this happening.
“with good quality gloves allergic reactions are relatively uncommon, what is much more common is the irritant reaction due to the effect of occlusion”
Irritant damage to the skin is different in that all irritants will affect everyone’s skin to some extent, although, as already stated, this damage will usually initially be asymptomatic. Unfortunately, one of the most common causes of such damage and ultimately the occupational irritant contact dermatitis is water due to what is termed ‘wet work’, but also from wearing occlusive gloves.
An irritant is defined as any agent, physical or chemical, capable of producing cell damage. Everything can be an irritant if applied for sufficient time and in sufficient concentration. Water, being the most abundant element of the skin, is usually regarded as banal and gentle. However, the irritancy of water is beyond doubt. – From Dermatotoxicology, second edition, Zhai H, Maibach HI, CRC Press.
As has been explained, we lose water through the skin (TEWL) continuously. In addition, we may be transporting more water from sweat glands through the pores on to the surface of the skin. Normally this water will evaporate unhindered. What happens, then, when we place a waterproof covering – in the form of our chemical protective glove – over the skin?
The answer is that the water can no longer evaporate and is absorbed back into the skin creating a condition known as hyperhydration. Now whilst too little water is something undesirable, so is too much. Once the water has saturated the stratum corneum it will start to accumulate in the viable epidermis. This causes the cells there (keratinocytes) to respond. One of the outcomes is that they initiate a response that inhibits the production of what are known as natural moisturising factors (NMFs) through the deactivation of keratohyalin granules degradation. Keratohyalin granules are the main source of NMFs. NMFs are a complex of chemicals that enable corneocytes to bind the water they need to function correctly. So a reduction in NMFs results in a consequent reduction in the residual moisture level in the stratum corneum. This is then less able to function properly as a barrier. Once the occlusion, i.e. our glove, is removed the skin loses not only the ‘free’ water that is surplus to normal but also the water that should have been retained in the corneocytes. The result is that, usually without our being able to recognise this, the skin becomes dry and with a barrier that is less able to protect us from chemical and biological hazards.
An additional concern is that water, and particularly sweat, is itself irritant to the skin and can ultimately result in what has been described by one eminent dermatologist as ‘hydration dermatitis’.
There is also the fact that irritant damage to the skin, even at an asymptomatic level, triggers the creation of protein molecules known as cytokines. Some of these can create a condition in the skin that predisposes to the development of sensitisation and allergic reactions.
Managing skin damage due to hyperhydration
We should keep in mind that it is the occlusion, regardless of the material the glove is produced from, that is the cause of our problem. Also, that the skin condition is essentially irritant in nature and, as such, will affect every glove wearer.
It is obvious that, if possible, we need to prevent the development of hyperhydration and the damage that this can cause. The question is how we might achieve this.
One approach that has been promoted by some is a solution based on the assumption that it is the sweating underneath the glove that is the sole cause of the hyperhydration. The propose to prevent the hyperhydration by using a cream, usually containing aluminium chlorohydrate, to block the pores. The theory is that if the sweat cannot escape it cannot then be absorbed back into the skin. Unfortunately blocking the pores does not also inactivate the sweat gland. This will continue to produce sweat causing an increase in the duct from gland to pore. This then leaks allowing the sweat to reach the living cells in the viable epidermis.
“‘Prickly heat’ (miliaria), a condition often experienced in hot weather, is produced in certain areas of the body as a consequence of obstruction of the sweat ducts followed by leakage of sweat into the surrounding area so that small, thin-walled vesicles form around the duct of the sweat gland. Miliaria can occur, under heat stress, in sites rendered ‘anhidrotic’ by application of aluminium chloride”. – The human skin, Studies in Biology no. 164, The Institute of Biology
Furthermore, the cream will do nothing to prevent the emission through the skin on the water that we have identified as TEWL.
It is also perhaps relevant to note that aluminium chlorohydrate is a well-established skin sensitiser that they propose applying to skin underneath the gloves where it can be more easily absorbed into the skin.
What is needed is an arrangement that allows the moisture, both sweat and TEWL, to emerge from the skin and be held between the glove and the skin’s surface. This can be achieved quite simply by wearing a separate cotton glove underneath the occlusive glove and changing these regularly as they become saturated. They can, of course, be rinsed, dried and reused.
“what is needed is an arrangement that allows the moisture to emerge from the skin and be held between the glove and the skin’s surface”
“The negative effect on skin barrier function from occlusive gloves was prevented by the use of a cotton glove.” – Effect of glove occlusion on human skin – Long-term experimental exposure, Ramsing DW, Agner T, Contact Dermatitis 1996, 34, 258-2624
Indeed in Germany the Technical Regulations on Hazardous Substance regulations (TRGS401) state that where gloves are worn for more than two hours in total in any one eight hour shift cotton gloves should be worn.
Sometimes the comment is made that this approach reduces dexterity and is thus impractical for fine work. This can be resolved quite easily by removing approximately 1cm from the tip of each of the relevant fingers of the cotton glove, thereby restoring the original dexterity whilst still leaving sufficient of the cotton glove to absorb the moisture.
In the U.K. the guidance for the Personal Protective Equipment regulations also has a similar provision that is often overlooked. appendix II, paragraph 2.2. states: ‘2.2. PPE enclosing parts of the body to be protected As far as possible, PPE “enclosing” the parts of the body to be protected must be sufficiently ventilated to limit perspiration resulting from use; if this is not the case, it must if possible be equipped with devices which absorb perspiration.’
Gloves with an integral lining are seldom a suitable solution as once the lining has become saturated the glove must be removed, turned inside out, rinsed and dried, before it can be reused.
Summary
By using cotton gloves, it is possible to at least reduce the hyperhydration of the skin from the wearing of occlusive gloves. An additional measure that the author has found beneficial is that when such gloves are removed the hands are rinsed in lukewarm water and dried fully. A small amount of an emollient lotion (aka moisturiser) is then applied to restore the surface hydrolipidic film so that the skin can return to its normal condition.
