Topical steroids are used to treat a wide range of inflammatory skin conditions, from everyday eczema and contact dermatitis to more stubborn problems like psoriasis, lichen planus, and discoid lupus. They work by calming inflammation, reducing redness and swelling, and suppressing the immune activity that drives most itchy, irritated skin. Available in seven potency classes and multiple formulations, they’re one of the most commonly prescribed treatments in dermatology.
Conditions Treated by Potency Level
Not every skin condition calls for the same strength. Topical steroids are classified into seven potency classes, with Class I being the strongest and Class VII the mildest. The condition, its severity, and where it appears on the body all determine which class your provider selects.
High-potency steroids (Classes I through III) are reserved for tougher conditions: resistant atopic dermatitis, psoriasis on thick-skinned areas, lichen simplex chronicus, lichen sclerosus, discoid lupus, dyshidrotic eczema, hyperkeratotic eczema, severe poison ivy, and bullous pemphigoid. They’re also used for alopecia areata (patchy hair loss) and vitiligo.
Medium-potency options (Classes IV and V) cover a broad middle ground: moderate atopic dermatitis, nummular eczema, asteatotic eczema (dry, cracked skin common in older adults), seborrheic dermatitis, stasis dermatitis on the lower legs, and scabies-related inflammation after the mites have been treated. Short courses at this strength can also help with severe intertrigo, the raw irritation that develops in skin folds.
Low-potency steroids (Classes VI and VII) are the go-to for sensitive areas and milder problems. That includes facial dermatitis, eyelid dermatitis, diaper rash, mild intertrigo, and perianal inflammation. Hydrocortisone 1% or 2.5%, the weakest class, is available over the counter in many countries and is the version most people have used at home.
How They Work in the Skin
When you apply a topical steroid, the active ingredient passes through the outer skin layer and enters cells, where it binds to a receptor in the cell’s interior. That receptor then moves into the cell’s nucleus and interacts with DNA, dialing down the genes responsible for inflammation and dialing up genes that help resolve it. One key effect is reducing the release of arachidonic acid, a fatty acid that fuels the production of chemicals causing redness, swelling, and pain.
Beyond suppressing inflammation, topical steroids constrict small blood vessels in the skin. This is why redness fades quickly after application, sometimes within hours. They also slow the rapid turnover of skin cells (useful in psoriasis, where cells pile up too fast) and dampen local immune responses.
Choosing the Right Formulation
The same steroid comes in different vehicles: ointments, creams, lotions, and gels. The vehicle matters more than most people realize, because it affects how much medication your skin actually absorbs and how comfortable it feels to use.
Ointments are petroleum-based and the most potent vehicle because they trap moisture and increase absorption. They work best on dry, thick, scaly patches but feel greasy, and they should be avoided in hairy areas and skin folds, where they can cause irritation or clogged follicles.
Creams are the most commonly prescribed form. They’re lighter, easier to spread, and cosmetically more acceptable. The trade-off is slightly lower absorption than an ointment, and the preservatives in many creams can occasionally irritate sensitive skin.
Lotions work well in hairy areas and skin folds because they spread easily and leave minimal residue. They contain alcohol, which gives them a drying effect that helps with oozing or weeping lesions but may sting on broken skin. Gels are also alcohol-based and dry quickly, making them a good choice for the scalp or oily skin.
How Much to Apply
A practical measuring system called the fingertip unit (FTU) takes the guesswork out of application. One FTU is the amount of cream or ointment squeezed from a standard tube along the length of an adult’s fingertip, from the crease of the finger to the tip. For an adult male, that’s about 0.5 grams; for an adult female, about 0.4 grams.
General guidelines for adults:
- One hand: 1 FTU
- One arm: 3 FTUs
- One foot: 2 FTUs
- One leg: 6 FTUs
- Face and neck: 2.5 FTUs
- Trunk (front and back): 14 FTUs
- Entire body: about 40 FTUs
For children around age 4, use roughly one-third of the adult amount. For infants between 6 months and 1 year, about one-quarter.
Sensitive Areas Need Lower Strength
Skin thickness varies dramatically across the body, and thinner skin absorbs far more medication. The face, eyelids, groin, armpits, and diaper area all have thin skin where absorption is highest. Only low-potency steroids should be used in these zones. On the other end of the spectrum, the palms and soles have the thickest skin and the lowest absorption, so they often require mid- to high-potency products to see any effect.
Warm, moist, or occluded skin also absorbs more. Skin folds (under breasts, in the groin) stay warm and opposed, naturally boosting steroid penetration. Covering treated skin with bandages or dressings amplifies this further, which is sometimes done intentionally for stubborn patches but increases the risk of side effects.
Using Topical Steroids in Children
Children, especially infants, have a higher ratio of skin surface area to body weight, which means they absorb proportionally more medication into their bloodstream. Infants generally need a less potent preparation than older children or adolescents for the same condition. The American Academy of Pediatrics recommends a straightforward rule: use the steroid twice a day when the skin is flaring and stop when things improve. High-potency preparations should be used very sparingly in children, and systemic side effects are most likely when potent agents are applied over large areas for extended periods in young infants.
Side Effects of Prolonged Use
Most side effects are local, developing at the site of application after prolonged or inappropriate use. The most common are skin thinning (atrophy), stretch marks (striae), rosacea-like redness, acne, perioral dermatitis (a bumpy rash around the mouth), and easy bruising. Less frequently, people notice increased hair growth at the application site, changes in skin pigmentation, or delayed wound healing. Existing skin infections can also worsen under a steroid, since the medication suppresses the local immune response.
Systemic side effects are uncommon with appropriate use but can occur when high-potency steroids cover large body areas over long periods. These include elevated blood sugar, increased eye pressure (glaucoma), and suppression of the body’s own cortisol production through effects on the hormonal feedback loop between the brain and adrenal glands.
Topical Steroid Withdrawal
Topical steroid withdrawal (TSW) is a condition that can develop after stopping prolonged topical steroid use. Symptoms include widespread skin redness, burning sensations, abnormal skin heat, itching, and peeling, sometimes even in areas where the steroid was never applied. NIH researchers have established provisional diagnostic criteria to help clinicians identify TSW, and a 2025 study found that people experiencing TSW symptoms had elevated levels of a specific metabolic marker (NAD+) in their blood and skin, which was within normal range in people without symptoms. TSW remains an area of active clinical attention, and the duration and severity vary widely between individuals.
When Topical Steroids Can Make Things Worse
One important caution: topical steroids should not be used on fungal skin infections. The CDC specifically warns against combination products that pair an antifungal with a corticosteroid. The most commonly prescribed combination contains a high-potency steroid that can worsen the fungal infection, lead to longer treatment times, increase side effects, and even promote antifungal resistance. If you have a fungal infection like ringworm or athlete’s foot, an antifungal without a steroid component is the better choice. The same principle applies to untreated bacterial infections, where suppressing the local immune response can allow the infection to spread.