Potential side effects

Emollients are commonly thought to have few side effects and it is true that generally patients can use these products without fear of unwanted outcomes. However, there are some factors that it is important to be aware of.

Contact dermatitis
Contact dermatitis is the term given to adverse inflammatory changes that occur in the skin when it comes into contact with certain products. Patients will sometimes complain of transient stinging or discomfort when a product is applied. This is not unusual and may be caused by the application of a substance to inflamed and broken skin rather than by any true sensitivity. This cannot be described as a true contact dermatitis. However, if the discomfort is more than just transient it may represent a true contact dermatitis; in other words, the patient is experiencing an irritant or allergic reaction to some ingredient within the product.

An allergic contact dermatitis is an immunemediated response to a product; once the patient has been sensitised they will react to the product even if they come into contact with only a small amount of it. The severity of the reaction may increase if exposure to the allergen is increased. The reaction may be immediate or can be delayed for 48–96 hours after the contact (Nicol et al., 1995). An immediate response is known as a Type 1 or an IgE-mediated response. It can be mild or in severe cases the individual may go into anaphylactic shock. A delayed response is known as a Type 4 or T-cell-mediated response.

In contrast an irritant contact dermatitis is a non-immune-mediated reaction where the skin reacts immediately or within hours. The adverse response can occur after a period of cumulative use, e.g. after frequent hand washing. In this instance no response is seen initially, but repeated use of a product causes inflammation. Alternatively, an irritant contact response can occur immediately after contact with a substance.

If a contact dermatitis is suspected, patch testing may be an appropriate way to investigate the precise cause of the inflammation (see Eczema for further details on patch testing). Whilst this process may be able to determine the nature of the allergen or irritant, it may then be almost impossible to determine whether it is present in commercial preparations.

It is most common for the excipients to act as sensitisers rather than the active ingredients themselves. Common irritants/allergens include perfumes and preservatives (de Groot, 2000). It is thought that for around 1% of the population, fragrances act as sensitisers and that for those with eczema this percentage increases to around 14% (de Groot, 2000). It is good practice, therefore, to recommend that people with sensitive skin use products that are truly fragrance free. It can be difficult to find absolutely fragrance-free products as many contain masking fragrances. Most prescribable products in the UK are fragrance free.

In order to reduce the impact of any potential adverse reactions when applying emollients, patients should be advised to apply a small ‘test patch’ to an area of their body (the inner arm is a good place to use). This should be left for 48 hours; if no adverse reaction is seen, the product is most likely to be safe to use extensively.

Another issue when considering potential adverse effects of emollients is the importance of using the product correctly, both the correct amount and in the correct way. For example a product that is used extensively in a way that it was not designed for, is aqueous cream. Originally designed as a wash product (i.e. to be applied to the skin as a soap substitute and then washed off), it has become a commonly used leave-on emollient. For many people this does not create any problems, although it is not a particularly effective emollient for those with dry skin. However, Cork et al. carried out an audit which showed that when aqueous cream was used as a leave-on product for children with eczema, it caused a significantly higher level of stinging and discomfort than other emollient products (Cork et al., 2003). Interestingly, the same audit showed that when aqueous cream was used as a wash product, it did not cause the same level of adverse reactions, and was an acceptable product. This audit emphasises the importance of using products in the way that they were designed for; this will help reduce adverse reactions.

Adverse effects caused by the occlusive nature of emollients
Greasy topical emollients can result in painful pustules caused by the blockage and consequent infection of the hair follicle; this is known as folliculitis. This can usually be avoided by correct application of emollients, i.e. in the direction of the lie of the hair. Changing the emollient to a lighter, less greasy one may be enough to resolve the problem; if not it may be necessary to stop emollient application for a time until the folliculitis resolves. Occasionally, topical or even oral antibiotics may be needed. If there is a high bacterial load on the skin caused by poor hygiene, folliculitis may be more likely if an occlusive emollient is applied. This will be aggravated further by hot, humid climatic conditions.


In dry, hot environments occlusive emollients may reduce heat loss through the skin. The lipids act as an insulator decreasing evaporation from the skin and thus affecting thermoregulation. This may be particularly important in small children who have a high surface area to volume ratio. In an adult or older child, thick occlusive emollients may feel very uncomfortable in hot weather. So choosing a lighter, less greasy emollient is preferable.

Other safety concerns
Emollients of all types, but particularly bath oils and soap substitutes, can make the skin and the bath or shower feel slippery. Caution needs to be taken especially with vulnerable groups like babies and older people to prevent accidents.

Another potential safety concern involves the flammability of paraffin-based emollients when they are soaked into a fabric. Thus dressings or clothing that have absorbed quantities of emollients that are primarily paraffin based (which includes most ointments) are at risk of catching fire if they come into contact with a naked flame. Patients should be advised not to smoke or come into contact with any type of flame if they are wearing paraffin-soaked garments or bandages (British Medical Association and Royal Pharmaceutical Society of Great Britain, 2007).