INTRODUCTION
Hyperkeratotic psoriatic lesions (plaques that present with severe elevation and scaling) develop from dysregulated proliferation and differentiation of keratinocytes and may be difficult to treat with topical therapy owing to impaired penetration of active ingredients.1-3 Patients with moderate-to-severe scaling experience lower quality of life compared to patients with no-to-mild scaling.4 Therapies that induce long-term remittance by modulating genetic pathways driving inflammation and hyperkeratosis may mitigate these negative sequelae of psoriasis.
Topical corticosteroids (TCSs) have been a mainstay of psoriasis treatment because of their rapid and localized effect, antiinflammatory and antiproliferative properties, and safety when used according to current guidelines.5,6 However, thick hyperkeratotic plaques frequently require treatment with ultrahigh potency TCSs,6 and complete skin clearance may be less likely to occur in patients with thick- versus thin-plaque disease,2 suggesting reduced skin penetration.7 In addition, because of concerns regarding skin atrophy, use of most TCSs is limited to 2 to 4 weeks.6 An exception is halobetasol propionate (HP; 0.01%) lotion, a potent-to-superpotent TCS approved for 8 weeks of continuous use.8
To reduce this risk, TCS is used in combination with the retinoid tazarotene (TAZ),9 which normalizes keratinocyte differentiation and hyperproliferation by modulating the expression of psoriasis-associated genes and antagonizing the signaling of inflammatory mediators.10,11 TAZ is associated with remittance of psoriasis after treatment discontinuation.12,13 However, TAZ alone may cause local skin irritation,9 such as pruritus, erythema, and burning,12 and therefore is not frequently used as monotherapy. The complementary mechanisms of action of TAZ and TCSs, such as HP, in psoriasis warrant their use as a combination therapy to maximize therapeutic benefits and mitigate risks.11
Topical corticosteroids (TCSs) have been a mainstay of psoriasis treatment because of their rapid and localized effect, antiinflammatory and antiproliferative properties, and safety when used according to current guidelines.5,6 However, thick hyperkeratotic plaques frequently require treatment with ultrahigh potency TCSs,6 and complete skin clearance may be less likely to occur in patients with thick- versus thin-plaque disease,2 suggesting reduced skin penetration.7 In addition, because of concerns regarding skin atrophy, use of most TCSs is limited to 2 to 4 weeks.6 An exception is halobetasol propionate (HP; 0.01%) lotion, a potent-to-superpotent TCS approved for 8 weeks of continuous use.8
To reduce this risk, TCS is used in combination with the retinoid tazarotene (TAZ),9 which normalizes keratinocyte differentiation and hyperproliferation by modulating the expression of psoriasis-associated genes and antagonizing the signaling of inflammatory mediators.10,11 TAZ is associated with remittance of psoriasis after treatment discontinuation.12,13 However, TAZ alone may cause local skin irritation,9 such as pruritus, erythema, and burning,12 and therefore is not frequently used as monotherapy. The complementary mechanisms of action of TAZ and TCSs, such as HP, in psoriasis warrant their use as a combination therapy to maximize therapeutic benefits and mitigate risks.11
