Emollients

Learning objectives
Pharmacology
Adverse effects
Activity

Learning objectives

• Recommend or prescribe emollients appropriately and safely

Pharmacology

Emollients soften skin and moisturisers add moisture. They are used to correct dryness and scaling of the skin and are an effective treatment for mild irritant contact dermatitis.

Dry skin results from lack of water in the stratum corneum. Water loss from the skin is increased by low humidity, wind, increasing age, diuretics, hypothyroidism and loss of sebum. Sebum is removed by washing with hot water and soap, detergents and solvents. Scaly skin arises from partial detachment of groups of corneocytes from the skin surface and is especially prominent in eczema, psoriasis and ichthyosis.

To correct dry skin, reduce bathing, use a non-soap cleanser and apply a moisturiser or emollient.

• Occlusives provide a layer of oil on the surface of the skin to slow water loss and thus increase the moisture content of the stratum corneum.
• Humectants included glycerine, urea and alpha hydroxy acids such as lactic acid or glycolic acid. They increase the water holding capacity of the stratum corneum and they also have a peeling or keratolytic action.

Occlusive emollients consist of oils of non-human origin (wool-fat, mineral oil etc.), either in pure form or mixed with varying amounts of water through the action of an emulsifier to form a lotion or cream. A large variety are available, reflecting that there is no ‘right’ moisturiser for all patients; the most suitable one often having to be found by trial and error.

• Bath oil deposits a thin layer of oil on the skin upon rising from the water.
• Lotions are more occlusive than oils and are best applied immediately after bathing, to retain the water in the skin, and at other times as necessary.
• Creams are more occlusive again. They include aqueous cream, cetomacrogol cream, oily cream.
• Ointments are the most occlusive, and include emulsifying ointment and white soft paraffin.
• The most occlusive of these are called protectives or barriers and contain dimethicone or similar compounds.

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 on the face, trunk and limbs. Creams are suitable for moderate dry skin. Ointments are recommended for very dry scaly areas, but many patients find them too greasy. Aqueous cream is a good all-round moderate-strength moisturiser that suits many patients because it is non-greasy, cheap and available in bulk with or without prescription. Because it contains an emulsifier, aqueous cream can mix with sweat and it can be washed off. Aqueous cream can be made greasier to suit individual preferences by adding white soft paraffin. Typically, 250g (or ml) to 1Kg (1l) are needed and liberal and regular usage is to be encouraged.

Humectant / keratolytics are particularly important in management of the ichthyoses (inherited or acquired scaly disorders of the skin) but urea and lactic acid preparations often sting if applied to scratched, fissured or dermatitic skin.

Adverse effects

Adverse reactions to emollients include:

• Irritant reactions: burning or stinging, especially common in atopic dermatitis.
• Contact allergy: uncommon and difficult to identify. Suspected contact allergy can be investigated by patch testing.
• Folliculitis: occlusion may result in sterile folliculitis or infection.
• Facial rashes: emollients may aggravate acne or cause perioral dermatitis.

Activity

Find out which emollients are fully funded on prescription. Discuss indications for their use.

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