Topical corticosteroids

Topical corticosteroids are highly effective as treatments for inflammatory skin conditions and a mainstay of treatment for eczema. They inhibit the production and action of inflammatory mediators in the skin. It is important for patients to understand that topical corticosteroids relieve symptoms but do not cure eczema.

The appropriate potency for the severity and extent of eczema together with the correct application of topical corticosteroids is essential to reducing the risk of adverse effect. Topical corticosteroids should be used intermittently to control acute eczema exacerbations and reduce inflammation and itching. They are applied in conjunction with emollients but applied at a different time of day to avoid diluting the steroid. The British National Formulary (BNF) (British Medical Association and Royal Pharmaceutical Society of Great Britain, 2009) classifies topical corticosteroids as mild, moderately potent, potent or very potent. Examples of topical corticosteroids available for prescription are listed in Table 9.5; details of constituent elements, such as antimicrobials, are given in the current BNF (British Medical Association and Royal Pharmaceutical Society of Great Britain, 2009).

Table 9.5 Topical corticosteroids and their potencies.   Potency   Formulation   Proprietary name   Mild   Hydrocortisone 0.1–2.5%   Dioderm, Efcortelan, Mildison     With antimicrobials   Canesten HC (e.g. miconazole), Daktacort, Econacort, Fucidin H, Nystaform-HC, Timodine, Vioform-Hydrocortisone     With crotamiton   Eurax-Hydrocortisone     Fluocinolone acetonide 0.0025%   Synalar 1 in 10 dilution   Moderately potent   eg: Clobetasone butyrate*   Betnovate-RD, Eumovate*, Haelan, Modrasone, Synalar 1 in 4 dilution, Ultralanum Plain     With antimicrobials   Trimovate     With urea   Alphaderm, Calmurid HC   Potent   eg: Betamethasone valerate 0.1% eg: Mometasone furoate*   betamethasone valerate 0.1%, Betacap, Bettamousse, Betnovate, Cutivate, Diprosone, Elocon*, hydrocortisone butyrate, Locoid, Locoid Crelo, Metosyn, Nerisone, Synalar     With antimicrobials   Aureocort, Betnovate-C, Betnovate-N, FuciBET, Locoid C, Lotriderm, Synalar C, Synalar N, Tri-Adcortyl     With salicylic acid   Diprosalic   Very potent   eg: Clobetasol propionate*   Dermovate*, Nerisone Forte, Clarelux, Etrivex     Source: Adapted from the British National Formulary (March 2009). Reproduced from National Collaborating Centre for Women's and Children's Health, Atopic Eczema in Children: Management of atopic eczema in children from birth up to the age of 12 years. Clinical Guideline. RCOG Press; 2007. © Royal College of Obstetricians and Gynaecologists; reproduced with permission.

In general, potent and very potent topical corticosteroids should be reserved for recalcitrant dermatoses and avoided on the face and skin flexures and in children (unless prescribed by a dermatology specialist). The least-potent topical corticosteroid that relieves symptoms should be applied (British Medical Association and Royal Pharmaceutical Society of Great Britain, 2009). Mild and moderately potent topical corticosteroids are associated with few side effects. However, particular care is required in the use of potent and very potent topical corticosteroids. As a guide, clinicians should consider the factors outlined in Table 9.6 when prescribing topical corticosteroids and assessing the risk of side effects.

Table 9.6 Factors to consider when prescribing topical corticosteroids for eczema.   Factors to consider Practical application   Potency Mild – moderate, children, face and flexures. Potent – for the body. Very potent – for the soles.   Degree of penetration Occlusion will increase potency. Ointments are better for penetrating dry, scaly lesions. Creams are better for moist, weeping lesions.   Extent of area treated Single lesion/generalised area.   Daily volume Grams per day. How long does a tube last?   Age of patient Children and the older person with fragile skin require lower potencies.

The current recommendation is to apply topical corticosteroids thinly to the affected area; no more frequently than twice daily and use the least-potent formulation which is fully effective (NICE, 2004a; BNF, 2009). We would advocate the use of the Finger-Tip Unit (FTU) here to enable more precise measurement of the topical steroid being used. Further deatils are given later.

Systemic side effects are not common and occur through skin absorption and can rarely cause adrenal suppression and Cushing’s syndrome. Absorption is likely to be greatest where skin is thin, broken and in flexural areas. Local side effects are outlined in Box 9.2.

Box 9.2 Potential local side effects from topical corticosteroids Spread and worsening of untreated infection Thinning of the skin, which may be restored over a period after stopping treatment but the original structure may never return Irreversible striae atrophicae and telangiectasia Contact dermatitis Perioral dermatitis Acne, or worsening of acne or rosacea Mild depigmentation which may be reversible Hypertrichosis also reported

Topical corticosteroid application
A practical measure devised for a practical measurement technique for the application of topical corticosteroids is the Finger Tip Unit (FTU) (Long and Finlay, 1991). One FTU is the amount of cream/ointment squeezed from the tip of an adult index finger to the first crease of the finger tip. One FTU (approximately 500 mg) is sufficient to cover an area that is twice that of the flat adult palm. For treating children, an adult FTU is used but the amount of FTUs are reduced depending on the age of the child (see Figure 9.11). The use of the FTU helps patients to understand how much topical corticosteroid to apply to ensure full therapeutic effectiveness. Current treatment guidelines recommend that topical corticosteroids should be stepped up or down according to severity and clinical response (NICE, 2007). Topical corticosteroids should be used to treat inflamed eczema (flare-ups), and in between flares, periods of using emollients only are advised.

Figure 9.11 Diagram of FTU and chart with FTUs for treating adults and children.