Erosive lichen planus (ELP) is a severe inflammatory disorder of mucosal tissues, with genital involvement causing significant morbidity. Its management is challenging, often requiring systemic therapy with limited durability and considerable side effects. Infectious triggers have been suggested but remain understudied.

A white male in his mid-40s developed erosive genital lichen planus following escalation of symptoms from a chronic polymicrobial genitourinary infection. Symptoms began in February 2017, with biopsy confirmation in November 2020. Flare-ups correlated with infection activity. Following orchiectomy, the patient was treated with twice-weekly phototherapy and daily oral palmitoylethanolamide (PEA) 800 mg. This regimen produced a substantial reduction of erosions, improved function, and restored quality of life without adverse events.

This case demonstrates effective long-term management of erosive genital lichen planus using a non-steroidal regimen of phototherapy and PEA. The results highlight the need to investigate infection-related triggers and to explore safe, multimodal alternatives for refractory disease.

Introduction

Lichen planus is a chronic autoimmune disorder affecting skin, hair, nails, and mucous membranes (Gorouhi et al., 2014). The erosive variant is particularly debilitating when localized to the genital mucosa, causing pain, ulceration, and impaired sexual function. Chronic erosive disease may also lead to scarring, urethral strictures, and malignant transformation (Usatine & Tinitigan, 2011). In this particular case, it is also believed to have led to Peyronie's Disease (Robertson, 2025).

Pathogenesis is thought to involve T-cell-mediated destruction of basal keratinocytes (Deng et al., 2023; Shao et al., 2019). Various triggers have been proposed, including viral infections, systemic medications, and dental restorative materials. Among infectious associations, the hepatitis C virus is the most studied (García-Pola et al., 2023); other bacterial or polymicrobial processes have been less well characterized.

Management of erosive lichen planus is difficult (Didona et al., 2022; Ho & Hantash, 2012). Corticosteroids, calcineurin inhibitors, systemic retinoids, and immunosuppressants are frequently employed, but their efficacy is inconsistent, and long-term toxicity limits use (Husein‐ElAhmed et al., 2019; Solimani et al., 2021). Phototherapy and nutraceuticals have shown promise but are underreported in genital variants.

This case is notable for its association with a polymicrobial genitourinary infection (bacterial) and its successful management using combined phototherapy and PEA.

Case Presentation

A white male in his mid-40s, otherwise healthy and of normal weight, presented with persistent erosive lesions of the glans penis.

History:

Symptoms began in February 2017 following the escalation of a chronic polymicrobial genitourinary infection. Episodes of dysuria and urethral discharge preceded recurrent erosions. Flares coincided with infection exacerbations. Despite supportive measures, symptoms persisted.

Diagnosis:

In November 2020, a biopsy of the glans performed by a dermatologist revealed lichenoid interface dermatitis with basal cell degeneration and dense inflammatory infiltrates, confirming erosive lichen planus. The inflammation was reported as severe. Oral mucosal lesions consistent with lichen planus were also present but not considered erosive.

Treatment and Clinical Course:

After an inguinal orchiectomy, which reduced systemic inflammatory burden but did not resolve mucocutaneous disease, therapy was initiated with:

• Phototherapy administered biweekly, with gradual titration to tolerance. Time is typically ~1 minute of exposure in each area with little overlap.

• Palmitoylethanolamide (PEA) 800-1200 mg daily, selected for anti-inflammatory and analgesic properties.

The patient experienced significant improvement over subsequent months, with near-complete resolution of erosions, decreased pain, and restoration of sexual function. Oral lesions improved in parallel. No adverse effects were reported.

Discussion

This case provides insight into three key aspects of erosive lichen planus management:

1. Infectious Triggers

The temporal association between infection exacerbations and lesion flares suggests polymicrobial infection may act as a persistent antigenic stimulus sustaining lichenoid inflammation. While hepatitis C is well documented as a trigger for erosive lichen planus, there is evidence to suggest that other infective causes exist (Lodi et al., 2010). This particular case raises the possibility that other chronic or stealth infections may play a comparable role.

2. Conventional Therapies and Limitations

Standard regimens rely heavily on corticosteroids, which often produce short-term benefit but are limited by atrophy, candidiasis, and systemic toxicity (Caramori et al., 2019). Calcineurin inhibitors avoid atrophy but are associated with burning, infection risk, and high cost (Schmitt et al., 2011). Retinoids and systemic immunosuppressants are options for refractory disease but carry hepatotoxicity, teratogenicity, and infection risks (Abuarij et al., 2024; Bressan et al., 2010). These limitations demonstrate a need for safer, sustainable therapies.

3. Novelty of Phototherapy and PEA

Phototherapy is well established for cutaneous lichen planus but is less commonly reported for genital erosive variants (Helgesen et al., 2015; Safari‐Kish et al., 2024). Its ability to induce apoptosis in activated T lymphocytes makes it biologically plausible and (Lee et al., 2013; Yu & Wolf, 2020), in this case, clinically effective.

Palmitoylethanolamide (PEA), an endogenous fatty acid amide, represents a novel therapeutic addition. Through activation of PPAR-α and modulation of mast cells and glial cells, it dampens inflammatory signaling and pain without inducing systemic immunosuppression (Basu, 2024; Keppel-Hesselink, 2012). Its favorable safety profile, affordability, and tolerability distinguish it from conventional agents. The complementary mechanisms of phototherapy and PEA likely account for the durable improvement observed in this case.

Clinical Implications

For patients with erosive lichen planus unresponsive or intolerant to conventional agents, this regimen offers a viable low-cost alternative. Furthermore, this case suggests that evaluation of infectious comorbidities should be prioritized, as their management may influence disease activity. In this particular case, it is currently believed that a chronic-low-grade polymicrobial genitourinary infection involving Corynebacterium pseudogenitalium and Gardnerella vaginalis is responsible (Robertson, 2025).

Future Directions

Larger studies are needed to assess the role of PEA as an adjunct or alternative in erosive lichen planus and to evaluate the safety and efficacy of phototherapy for genital (or other) involvement. Exploration of infection-driven immune activation may also broaden our understanding of disease pathogenesis.

Limitations

This is a single case report, and causality cannot be firmly established. The concurrent orchiectomy and intermittent use of N-acetylcysteine complicate interpretation, as systemic inflammatory load may have influenced outcomes. Nevertheless, when the proposed treatment was withheld, the condition demonstrated a gradual yet measurable recurrence, typically emerging over several weeks. Finally, while speculative and requiring further investigation, these findings may also provide additional support for the infection–disease relationship in this case.

Conclusion

Erosive genital lichen planus is difficult to treat and profoundly affects quality of life. In this case, a combination of biweekly phototherapy and daily oral palmitoylethanolamide achieved substantial and durable disease control without adverse effects. This regimen represents a promising, non-steroidal alternative for refractory disease and demonstrates the potential role of infection in disease pathogenesis. Further investigation is warranted to establish efficacy and guide broader clinical adoption.

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Resources:

Abuarij, M., Alyahawi, A., & Alkaf, A. (2024). The current trends of psoriasis treatment in dermatological practice. Universal Journal of Pharmaceutical Research.

Basu, D. (2024). Palmitoylethanolamide, an endogenous fatty acid amide, and its pleiotropic health benefits: A narrative review. The Journal of Biomedical Research, 39(3), 215-228.

Bressan, A. L., Silva, R. S. D., Fontenelle, E., & Gripp, A. C. (2010). Immunosuppressive agents in Dermatology. Anais brasileiros de dermatologia, 85, 9-22.

Caramori, G., Mumby, S., Girbino, G., Chung, K. F., & Adcock, I. M. (2019). Corticosteroids. In Nijkamp and Parnham's Principles of Immunopharmacology (pp. 661-688). Cham: Springer International Publishing.

Deng, X., Wang, Y., Jiang, L., Li, J., & Chen, Q. (2023). Updates on immunological mechanistic insights and targeting of the oral lichen planus microenvironment. Frontiers in Immunology, 13, 1023213.

Didona, D., Caposiena Caro, R. D., Di Stasio, D., Di Carlo, S., Contaldo, M., & Romano, A. (2022). Therapeutic strategies for oral lichen planus: State of the art and new insights. Frontiers in Medicine, 9, 997190. https://www.frontiersin.org/articles/10.3389/fmed.2022.997190/full

García-Pola, M., Rodríguez-Fonseca, L., Suárez-Fernández, C., Sanjuán-Pardavila, R., Seoane-Romero, J., & Rodríguez-López, S. (2023). Bidirectional association between lichen planus and hepatitis C—an update systematic review and meta-analysis. Journal of Clinical Medicine, 12(18), 5777.

Gorouhi, F., Davari, P., & Fazel, N. (2014). Cutaneous and mucosal lichen planus: a comprehensive review of clinical subtypes, risk factors, diagnosis, and prognosis. The Scientific World Journal, 2014(1), 742826.

Helgesen, A. L. O., Warloe, T., Pripp, A. H., Kirschner, R., Peng, Q., Tanbo, T., & Gjersvik, P. (2015). Vulvovaginal photodynamic therapy vs. topical corticosteroids in genital erosive lichen planus: a randomized controlled trial. British Journal of Dermatology, 173(5), 1156-1162.

Ho, J. K., & Hantash, B. M. (2012). Systematic review of current systemic treatment options for erosive lichen planus. Expert Review of Dermatology, 7(3), 269-282.

Husein‐ElAhmed, H., Gieler, U., & Steinhoff, M. (2019). Lichen planus: a comprehensive evidence‐based analysis of medical treatment. Journal of the European Academy of Dermatology and Venereology, 33(10), 1847-1862.

M Keppel Hesselink, J. (2012). New targets in pain, non-neuronal cells, and the role of palmitoylethanolamide.

Lee, C. H., Wu, S. B., Hong, C. H., Yu, H. S., & Wei, Y. H. (2013). Molecular mechanisms of UV-induced apoptosis and its effects on skin residential cells: the implication in UV-based phototherapy. International Journal of Molecular Sciences, 14(3), 6414-6435. https://www.mdpi.com/1422-0067/14/3/6414

Lodi, G., Pellicano, R., & Carrozzo, M. (2010). Hepatitis C virus infection and lichen planus: a systematic review with meta‐analysis. Oral diseases, 16(7), 601-612.

Robertson, D. (2025, April 9). Persistent Polymicrobial Genitourinary Infection and Associated Autoimmune Sequelae in a Male. https://www.dmrpublications.com/polymicrobial-genitourinary-infection/

Safari‐Kish, B., Bidares, M., Zaresharifi, S., Malekzadeh‐Shoushtari, H., Aziz, M., Salehi, M., & Zahedi, K. (2024). Treatment strategies for erosive genital lichen planus: A systematic review of therapeutic modalities and emerging breakthroughs. Health Science Reports, 7(10), e70129.

Schmitt, J., von Kobyletzki, L., Svensson, Å., & Apfelbacher, C. (2011). Efficacy and tolerability of proactive treatment with topical corticosteroids and calcineurin inhibitors for atopic eczema: systematic review and meta-analysis of randomized controlled trials. British Journal of Dermatology, 164(2), 415-428. https://academic.oup.com/bjd/article-abstract/164/2/415/6643974

Shao, S., Tsoi, L. C., Sarkar, M. K., Xing, X., Xue, K., Gudjonsson, J. E., & Kahlenberg, J. M. (2019). IFN-γ enhances cell-mediated cytotoxicity against keratinocytes via JAK2/STAT1 in lichen planus. Science Translational Medicine, 11(509), eaav7561. https://www.science.org/doi/abs/10.1126/scitranslmed.aav7561

Solimani, F., Forchhammer, S., Schloegl, A., Ghoreschi, K., & Meier, K. (2021). Lichen planus–a clinical guide. JDDG: Journal der Deutschen Dermatologischen Gesellschaft, 19(6), 864-882.

Usatine, R. P., & Tinitigan, M. (2011). Diagnosis and treatment of lichen planus. American family physician, 84(1), 53-60.

Yu, Z., & Wolf, P. (2020). How it works: the immunology underlying phototherapy. Dermatologic Clinics, 38(1), 1–10. https://www.derm.theclinics.com/article/S0733-8635(19)30083-X/abstract

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Author:
Dr. David M Robertson
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