Corticosteroids are naturally occurring hormones in the human body that play a central role in a wide range of physiological processes including immune system response, the regulation of inflammation, metabolising carbohydrates and maintaining blood electrolyte levels.
What are topical corticosteroids used for?
The term topical corticosteroid refers to any sort of cream, gel or ointment that is typically used to treat common inflammatory skin conditions such as eczema and psoriasis. They are often referred to colloquially as ‘steroid creams’, with their primary purpose being the reduction of skin irritation and inflammation.
Topical corticosteroids are also used to treat a wide range of other treatments, including those that affect the nose (such as nasal polyps, hay fever and allergic rhinitis), ears (otitis externa) and eye allergies. They can also be used on other ailments such as insect bites and nappy rash.
Topical drugs can be classified in several categories that overlap, such as drying-agents, anti-itch agents, anti-infective agents, keratolytics (drugs that loosen, soften and increase exfoliation of the top layer of skin), anti-inflammatory agents and moisturising agents (emollients).
There are two prominent factors that influence the strength of the topical medication: the vehicle (the type of base in which the medication is contained) and type of corticosteroid. Corticosteroid delivery can be categorised into five different forms:
- Solutions (water or alcohol based liquids)
- Lotions (recommended for treating larger areas of skin, or areas of skin covered by hair)
- Creams (used on affected skin that is weeping, or has become moist)
- Ointments (liquids that contain high levels of oil and are often best used on dry and / or scaly skin)
- Gels (a more solidified corticosteroid, often used to treat extremely hairy areas such as the scalp)
The vehicles used in each category is an inactive ingredient mixed with the active ingredient (the drug) and controls the texture and consistency of each of the treatments within these categories i.e. light and watery like a solution, or thick and greasy like an ointment.
The choice of vehicle is determined by a number of factors: where on the body the drug will be applied, the level of convenience of application, how it will look, and whether or not the active ingredient is intended to penetrate or remain on the surface of the skin.
The type of vehicle also determines how the drug is transmitted – for example, ointments are much more efficacious in regards to delivering active ingredients into the skin (1), and they are also less irritating when compared to lotions, gels and solutions on application to open sores such as ulcers. Lotions are evidenced to be less effective than other categories such as creams, ointments and gels at delivering drugs and generally have a lower potency, yet the vehicle is the most effective method for being applied to hairy skin and cooling and/or drying inflamed lesions.
The term ‘potency’ when comparing different ingredients
Topical corticosteroids are classified by potency, ranging from Class 1 (super potent) to Class 7 (least potent). Those in the least potent category, such as hydrocortisone, are among the most common topical treatments found in over the counter medicines and prescriptions. Potency is a simple indicator of the strength of each treatment.
Benefits and concerns
Used appropriately, topical corticosteroids have been proven to be extremely effective in treating the symptoms of many common skin complaints (2). The majority of steroid treatments that are prescribed by doctors are often in Class 7, posing minimal risk and reducing the risk of some of the most commonly associated side effects including changing skin colour, increased vulnerability to infection and thinning of the skin.
Used sensibly, and in line with pharmaceutical guidelines, corticosteroids are considered a very safe treatment: most serious side effects as a result of use are often closely associated with excessive overuse of potent and super potent medications (3). Serious misuse of Class 1 and 2 treatments can lead to high blood pressure (hypertension) and hyperglycaemia (increase in blood sugar levels).
To such side effects, prescribing guidelines indicate that such medications are safest when administrated intermittently, with a proper dose/amount and over a correct time period.
Much of the historical thinning of skin (skin atrophy) associated with corticosteroid misuse was the result of prescriptions that did not specify the amount, duration and time that each medicine should be used for.
Other studies have highlighted a range of negative effects associated with misuse, including glaucoma and cataracts when used excessively on eyelids, and pink bumps and acne when used to excess on and around the face(4).
Cushing’s syndrome is a serious but rare condition associated with excessive steroid use, typified by rapid weight increase, thinning of the skin, and experiencing depression and anxiety (5).
High potency corticosteroids have been evidenced to inhibit adrenal gland function, particularly in children, with a 2014 retrospective case study of 59 children taking prolonged courses of glucocorticoids evidencing that 1 in 5 with steroid-dependent diseases would experience adrenal suppression (6).
When shouldn’t corticosteroids be used?
Topical medications should not be applied to infected skin, as they can significantly aggravate the symptoms and make them increasingly severe.
Mild or moderate topical treatments are considered safe during pregnancy, although research has suggested that the use of potent and super potent medication increases the risk of babies being born with a low birth weight (7). As a precautionary measure, pregnant women are also advised not to breastfeed if using super potent topical corticosteroids.
Children are able to use mild topical treatments, but are generally advised to avoid potent treatments. On occasions when children have severe symptoms, such as those associated with severe cases of atopic eczema, potent treatments can be used (often under the careful supervision of a consultant dermatologist).
References
- Paudel KS, Milewski M, Swadley CL, Brogden NK, Ghosh P, Stinchcomb AL (2010) Challenges and opportunities in dermal / transdermal delivery. Ther Deliv. Jul 2010; 1(1): 109-131
- Ference JD, Last AR (2009) Choosing topical corticosteroids. Am Fam Physician 2009 Jan 15;79(2): 135-40
- Chaffman MO (1999) Topical corticosteroids: a review of properties and principles of therapeutic use. Nurse Pract Forum. 1999 Jun;10(2):95-105.
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Topical Corticosteroids. Available online at http://cks.nice.org.uk/corticosteroids-topical-skin-nose-and-eyes#!scenario (last accessed 7th December 2014)
- Ritter A, Burow A, Vallelian F, Schaer D (1994) Systemic glucocortoids: diagnosis, prophylaxis and treatment of side effects. Praxis (Bern 1994). 2014 Aug 20;103(17):987-98; quiz 996. doi: 10.1024/1661-8157/a001747.
- Sidoroff M, Kolho KL (2014) Screening for adrenal suppression in children with inflammatory bowel disease discontinuing glucocorticoid therapy. BMC Gastroenterol. 2014 Mar 24;14:51. doi: 10.1186/1471-230X-14-51.
- Chi C-C, Wang SH, Kirtschig G et al. (2010) Systematic review of the safety of topical corticosteroids in pregnancy. J Am Acad Dermatol 62:694–705
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