Evidence-Based Management of Papulosquamous Disorders in Primary Care

Papulosquamous disorders—including psoriasis, lichen planus, and pityriasis rosea—are inflammatory dermatoses frequently seen in family and other primary care settings. While the conditions share overlapping presentations with papules and scales, their distinct pathophysiologies, associated comorbidities, and treatment paradigms underscore the importance of accurate diagnosis and tailored therapeutic approaches.

These and other dermatologic conditions were on the agenda during day 2 of the 2025 Family Medicine Experience (FMX) in Anaheim, California, October 5-9.

Psoriasis: A Multisystem Inflammatory Disease

Psoriasis affects approximately 3% of the US population and represents far more than a dermatologic condition.¹ The American Academy of Dermatology and National Psoriasis Foundation emphasize that psoriasis is a chronic, inflammatory multisystem disease requiring comprehensive management beyond skin-directed therapy.²

For mild-to-moderate plaque psoriasis affecting less than 5-10% body surface area, topical therapies remain first-line treatment.² Topical corticosteroids are the cornerstone of management, with use up to 12 weeks considered safe under physician supervision. Steroid-sparing agents, including vitamin D analogs (calcipotriene) and tazarotene, offer effective alternatives that can be combined with topical steroids to enhance efficacy while reducing steroid burden.

For moderate-to-severe disease affecting more than 10% body surface area or significantly impacting quality of life, phototherapy and systemic treatments become necessary.² Narrowband ultraviolet B phototherapy represents an effective intermediate option. Traditional systemic agents include methotrexate, cyclosporine, and acitretin. Biologic therapies have revolutionized management, particularly for patients with inadequate response to conventional agents. TNF-α inhibitors, IL-12/23 inhibitors, IL-17 inhibitors, and IL-23 inhibitors offer targeted immunomodulation with improved safety profiles.³ While dermatologists typically initiate biologic therapy, family physicians play crucial roles in monitoring treatment response and coordinating specialty care.

Screening for Cardiovascular and Metabolic Comorbidities. Given its etiology as a systemic inflammatory condition, clinicians should proactively screen individuals with psoriasis for cardiometabolic comorbidities. Compared with the general population, individuals with psoriasis are at increased risk for metabolic syndrome, with odds ratios as high as 2.26.⁴ The increased cardiovascular disease risk appears independent of traditional risk factors, suggesting that chronic systemic inflammation contributes to accelerated atherosclerosis. Shared inflammatory pathways, including TNF-α and IL-23/Th-17 cascades, promote both cutaneous and systemic inflammation.⁵

Clinicians should also routinely screen their patients with psoriasis for hypertension, dyslipidemia, diabetes mellitus, and obesity.⁶ Intensive risk factor modification should be regularly reinforced, including for smoking cessation, weight reduction, and aggressive lipid and blood pressure control.

Lichen Planus: Immune-Mediated Mucocutaneous Disease

Lichen planus, characterized by pruritic, polygonal, purple papules often affecting flexural surfaces, is a cell-mediated immune response against basal keratinocytes. Unlike psoriasis, lichen planus typically follows a self-limited course lasting 1-2 years, though mucosal involvement may persist longer.⁷

High-potency topical corticosteroids remain first-line therapy, with betamethasone dipropionate or clobetasol propionate applied twice daily until lesions resolve.⁷ Topical calcineurin inhibitors (tacrolimus, pimecrolimus) offer steroid-sparing alternatives, particularly for mucosal involvement where long-term corticosteroid use poses greater risk.

Oral lichen planus requires particular attention given its chronic nature and small but measurable malignant transformation risk (approximately 1-2% lifetime risk).⁸ Initial management is typically pursued with topical corticosteroids in gel or rinse formulations. Systemic corticosteroids may be necessary for severe disease, though their use should be limited to short courses.

For extensive or refractory lichen planus, the immunomodulatory effects of phototherapy with PUVA or NB-UVB may be required.⁷ Systemic immunosuppressants, including methotrexate, azathioprine, mycophenolate mofetil, and cyclosporine, are reserved for severe, recalcitrant cases. The overlapping efficacy for lichen planus and psoriasis of these immune-modulating agents is thought to be the result of the conditions’ shared inflammatory pathways.

Pityriasis Rosea: Self-Limited Viral-Associated Eruption

Pityriasis rosea presents distinct management considerations given its self-limited nature and suspected viral etiology. The characteristic herald patch followed by a generalized eruption along Langer lines typically resolves spontaneously within 6-8 weeks, making reassurance and symptomatic management the primary interventions.⁹

Medium-potency topical corticosteroids and oral antihistamines effectively manage pruritus as the condition runs its natural course.⁹ Emollients and zinc oxide preparations provide additional symptomatic benefit. Unlike psoriasis and lichen planus, pityriasis rosea has shown only limited response to traditional immunosuppressive approaches.

High-dose acyclovir (800 mg 5 times daily) has proven effective in randomized controlled trials for severe cases, supporting a viral etiology and offering an intervention for individuals with significant symptoms.¹⁰ For those with severe or persistent disease, NB-UVB phototherapy accelerates resolution through immune modulation in the skin.⁹

Final Thoughts

Effective management of papulosquamous disorders requires attention to distinguish between these conditions, understand their distinct treatment paradigms, and a commitment to screening for associated comorbidities. While psoriasis, lichen planus, and pityriasis rosea share topical corticosteroids and phototherapy as common therapeutic modalities, their divergent natural histories, systemic involvement, and responses to systemic immunomodulation necessitate individualized approaches. Recognizing psoriasis as a systemic inflammatory condition with significant cardiovascular implications represents a critical paradigm shift that should inform screening practices and risk factor management in primary care.

References

1. Armstrong AW, Mehta MD, Schupp CW, et al. Psoriasis prevalence in adults in the United States. JAMA Dermatol. 2021;157(8):940-946.doi:10.1001/jamadermatol.2021.2007
2. Menter A, Strober BE, Kaplan DH, et al. Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics. J Am Acad Dermatol. 2019;80(4):1029-1072. doi: 10.1016/j.jaad.2018.11.057
3. Sbidian E, Chaimani A, Garcia-Doval I, et al. Systemic pharmacological treatments for chronic plaque psoriasis: a network meta-analysis. Cochrane Database Syst Rev. 2017;12(12):CD011535.doi: 10.1002/14651858.CD011535.pub2
4. Armstrong AW, Harskamp CT, Armstrong EJ. The association between psoriasis and metabolic syndrome: a systematic review and meta-analysis of observational studies. J Am Acad Dermatol. 2013;68(4):654-662. doi:10.1016/j.jaad.2017.04.1133
5. Boehncke WH, Schön MP. Psoriasis. Lancet. 2015;386(9997):983-994. doi:10.1016/S0140-6736(14)61909-7
6. Takeshita J, Grewal S, Langan SM, et al. Psoriasis and comorbid diseases: epidemiology. J Am Acad Dermatol. 2017;76(3):377-390. doi: 10.1016/j.jaad.2016.07.064.
7. Le Cleach L, Chosidow O. Lichen planus. N Engl J Med. 2012;366(8):723-732. doi:10.1056/NEJMcp1103641
8. Gonzalez-Moles MA, Warnakulasuriya S, Gonzalez-Ruiz I, et al. Malignant transformation risk of oral lichen planus: a systematic review and comprehensive meta-analysis. Oral Oncol. 2019;96:121-130. doi: 10.1016/j.oraloncology.2019.07.012
9. Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol. 2009;61(2):303-318. doi: 10.1016/j.jaad.2008.07.045
10. Amer A, Fischer H. Azithromycin does not cure pityriasis rosea. Pediatrics. 2006;117(5):1702-1705. doi: 10.1542/peds.2005-2450