Topical corticosteroids are applied to the skin to reduce inflammation. They are commonly used to treat a variety of skin disorders, such as atopic dermatitis, or psoriasis.
Low-strength formulations, such as 1% hydrocortisone, are available over-the-counter. However, stronger formulations used for chronic skin conditions are available only by prescription.
NOTE: Corticosteroids are different from "anabolic steroids", such as testosterone, that are sometimes abused by athletes and body builders to build muscle mass.
Strength of Topical Corticosteroids
The "strength" of a particular corticosteroid is determined by several factors including:
- The active ingredient used (clobetasol > betamethasone > hydrocortisone). Some compounds have a stronger effect when used at the same concentration.
- The concentration (2% > 1%). A medication with 2% concentration of hydrocortisone is more potent than a medication with 1% concentration of hydrocortisone.
- The formulation (ointment, solution, gel, solution, foam, or cream). The potency of an ointment is often greater than other formulations because the ointment keeps the skin hydrated, helping the medication to penetrate to deeper layers. Creams, because they absorb more quickly, have greater cosmetic appeal for most people so are often used on the face. As a result, 2% hydrocortisone ointment may be more potent than 2% hydrocortisone cream. Foams and solutions are useful for penetrating hair-bearing areas, such as the scalp.
Potency Ranking of Topical Corticosteroids
Specific formulations, or brands of topical corticosteroids have been ranked according to their potency on a scale of 1 to 7, with 1 being the most potent.
Group 1 (I) corticosteroids, such as clobetasol, are "super potent" and have the greatest risk of causing side effects if used for prolonged periods
Group 7 (VII) corticosteroids, such as 1% hydrocortison, are "low potency" and can be purchased without a prescription.
Medications in this group can be used more safely for longer periods of time, but they too must be used properly to prevent unwanted side effects.
Selecting a Corticosteroid Strength
Your doctor will prescribe a corticosteroid depending on several variables, including the following:
- the skin condition being treated
- the part of the body being treated
- the person's response to past treatments.
Some skin disorders, such as seborrheic dermatitis, are relatively sensitive to corticosteroids and usually respond well to less potent corticosteroids in Group 7 (VII) and 6 (IV).
Some more moderately resistant skin diseases, such as adult atopic dermatitis, nummular eczema, or allergic contact dermatitis may require slightly stronger corticosteroids in Group 5 (V) and 4 (IV).
Resistant skin diseases, such a plaque psoriasis and lichen planus may require treatment with the more potent corticosteroids in Group 2 (II) and 1 (I).
Because the skin on the elbows and knees is relatively thick, more potent corticosteroids can be used more safely on those sites.
Conversely, the skin of the face and genital area is very thin which means it absorbs the medication more easily. As result less potent corticosteroids are prescribed for those locations.
Side Effects from Corticosteroid Use
Group 1 and 2 formulations are generally not recommended for use longer than two weeks due to the increased risk of developing side effects.
Prolonged use of corticosteroids of any strength can lead to side effects, including the thinning of skin (atrophy).
Corticosteroids can also cause some skin conditions to worsen, including rosacea, fungal infections, and scabies. If used for longer than one month, they can create additional skin disorders including perioral dermatitis and steroid-related acne. Speak to your doctor if your skin condition worsens while on treatment.
If your skin condition gets under control following the use of a corticosteroid, your doctor will recommend stopping its use, reducing the number of times it is applied each week, or taking a less potent formulation. Other non-steroidal medications may also be prescribed, such as barrier creams, or calcineurin inhibitors (Elidel®, Protopic®)
Be sure to follow your doctor's instructions.