What are emollients and moisturisers?
Emollients are products used to soften skin. Moisturisers are products used to add moisture to the skin. There are numerous emollients and moisturisers on sale at general stores and pharmacies. Options include:
- Oils
- Lotions
- Creams
- Ointments.
Emollients and moisturisers are most effective when applied immediately after bathing but can also be applied at other times.
Why use emollients and moisturisers?
Uses of emollients and moisturisers include:
- To relieve dryness and scaling of the skin
- To disguise fine lines and wrinkles
- To treat mild irritant contact dermatitis
- As a base for make-up.
What do emollients and moisturisers contain?
Active ingredients of emollients and moisturisers are occlusives and humectants. They often include other ingredients, such as surfactants (non-soap cleansers), fragrances and preservatives.
Occlusive moisturisers
Occlusives are oils of non-human origin, often mixed with water and an emulsifier to form a lotion or cream. They provide a layer of oil on the surface of the skin to reduce water loss from the stratum corneum.
- Bath oil deposits a thin layer of oil on the skin upon rising from the water.
- Lotions are more occlusive than oils.
- Creams are more occlusive again. Thicker barrier creams containing dimethicone are particularly useful for hand dermatitis.
- Ointments are the most occlusive and include pure oil preparations such as equal parts of white soft and liquid paraffin or petroleum jelly.
The choice of occlusive emollient depends upon the area of the body and the degree of dryness and scaling of the skin.
- Lotions are used for the scalp and other hairy areas and for mild dryness elsewhere
- Creams are used when more emollience is required.
- Ointments are prescribed for dry, thick, scaly areas, but many patients find them too greasy.
Sorbolene and glycerine cream is a general-purpose moisturiser that is non-greasy, cheap and available in bulk without prescription.
The minimum quantity for an occlusive emollient is 250 g (or ml) and often 500 g or 1 kg is needed: liberal and regular usage is to be encouraged. How frequently it is applied depends on how dry the skin is: very dry skin may benefit from a greasy emollient every couple of hours, but slightly dry skin may only need a light moisturiser at night.
Humectants
Humectants increase the water holding capacity of the stratum corneum. They include:
- Glycerine
- Urea
- Alpha hydroxy acids such as lactic acid or glycolic acid.
- Salicylic acid
Urea and the acidic preparations often sting if applied to scratched or fissured skin. They are also keratolytic, ie they have a descaling or peeling effect, important in the management of ichthyosis.
Preservatives
Creams and lotions are prone to microbial contamination and preservatives are added to improve shelf life. Preservatives in moisturisers can lead to contact allergic dermatitis in sensitive individuals.
Other ingredients
Many additional agents may be added to a moisturiser to appeal to the consumer. Be aware that marketing claims for the effectiveness of many of these ingredients in reducing the signs of skin ageing can be misleading. Large molecules such as peptides and collagen cannot penetrate through the stratum corneum.
Adverse reactions to emollients
Irritant reactions
People with sensitive skin associated with atopic dermatitis or rosacea often describe irritant reactions to emollients and moisturisers such as burning and stinging. If irritation is transient, the product can continue to be used. It should be discontinued if contact dermatitis appears.
Contact allergy
Contact allergy to moisturisers and emollients is rare. Suspected contact allergy to preservative, fragrance or vehicle can be investigated by patch testing.
Folliculitis
Occlusive emollients can cause or aggravate acne, perioral dermatitis, folliculitis and boils.
Thermal burns
Thermal burns from paraffin-containing ointments on clothing or bedding can be dangerous and may occur if exposed to cigarettes or a lighted fire.