How are topical corticosteroids (topical steroids) classified based on potency?

Topical Corticosteroid Potency Classification

Topical corticosteroids are classified into 7 classes based on their vasoconstrictor potency, with Class 1 being ultra-high (superpotent) and Class 7 being the lowest potency. 1

The Seven-Class System

The American Academy of Dermatology uses a standardized classification based on skin vasoconstrictive activity:

Class 1 (Ultra-High/Superpotent Potency)

• Clobetasol propionate 0.05% 1
• Halobetasol propionate 0.05% 1
• Efficacy rates: 58%-92% 2, 1
• Limited to 2-4 weeks of continuous use due to high risk of adverse effects 1, 3

Class 2 (High Potency)

• Amcinonide 0.1% 1
• Betamethasone dipropionate 0.05% 1
• Fluocinonide 0.05% 1
• Efficacy rates: 68%-74% 2, 1
• Can be used for up to 4 weeks 1

Classes 3-4 (Upper Mid-Strength and Mid-Strength)

• Efficacy rates: 68%-72% 2, 1
• Can be used for up to 4 weeks for conditions like plaque psoriasis 1

Classes 5-7 (Low Potency)

• Hydrocortisone 1% and 2.5% 1
• Efficacy rates: 41%-83% 2, 1
• No specified time limit for use due to favorable safety profile 1, 3

Clinical Application Algorithm

Step 1: Anatomical Site Selection

• Face, neck, genitals, and intertriginous areas: Use Class 5-7 (low potency) only 2, 1
• Thick, chronic plaques on trunk/extremities: Consider Class 1 (ultra-high potency) 1
• Scalp: All classes can be used for up to 4 weeks 1

Step 2: Disease Severity Matching

• Severe disease/acute flares: Start with Class 1-2 (ultra-high to high potency) 2
• Moderate disease: Use Class 3-4 (mid-strength) 2
• Mild disease or maintenance: Use Class 5-7 (low potency) 2, 1

Step 3: Duration Strategy

• Initial control phase: Use higher potency agents short-term (2-4 weeks) 2, 1
• Maintenance phase: Transition to lowest effective potency or intermittent dosing (twice weekly) 2, 1

Critical Safety Considerations

High-Risk Anatomical Sites

The face and intertriginous areas have significantly increased absorption and atrophy risk—always use Class 5-7 in these locations regardless of disease severity. 2, 1 The increased skin permeability in these areas makes even mid-potency steroids potentially harmful. 1

Pediatric Populations

Children require lower potency agents (Class 6-7) and shorter treatment durations due to higher risk of systemic absorption and adrenal suppression. 1, 3 Their higher body surface area-to-weight ratio increases systemic exposure risk. 3

Common Adverse Effects

• Skin atrophy, striae, telangiectasia, purpura, and folliculitis 1
• Risk increases with: prolonged use, large application areas, higher potency, occlusion, and use on thin skin 3

Maintenance Therapy Approach

For long-term disease control, use intermittent application (once to twice weekly) of medium-potency steroids rather than continuous daily use. 2 A landmark study demonstrated that fluticasone propionate 0.05% used twice weekly after achieving control reduced relapse risk 7-fold compared to emollients alone (95% CI: 3.0-16.7; P < .001). 2

Application Frequency

• Most conditions: Once or twice daily application 2, 3
• Potent steroids: Once daily may be sufficient 2
• Maintenance: Once to twice weekly after disease control 2