Lichen planus is characterized by small, pruritic, polygonal, violaceous, flat-topped papules with or without umbilication, coalescence, Wickham striae, and Koebnerization on the flexor wrists, forearms, dorsal hands, shins, and presacrum. It is a rare disorder triggered by infection, vaccines, stress, contact allergens, or drugs in genetically predisposed individuals. It occurs in 0.2% to 1% of the population, with the highest incidence in people between the ages of 30 and 60. This condition can affect various parts of the body including the skin, oral cavity (75% of patients), scalp, nails, genitalia, and esophagus. Lichen striatus, lichen nitidus, erythema dyschromicum perstans, keratosis lichenoides chronica, actinic lichen nitidus, and annular lichenoid dermatitis (of youth) will also be discussed in this section. 

In this learning module, you will find a key point review on lichen planus and lichen dermatoses focused on epidemiology, pathogenesis, clinical features, differential diagnosis and management.

To test your knowledge, we refer you to the associated quiz (short answer format questions) and clinical vignettes simulating OSCE examinations.

We hope you find this module useful and if you choose to submit new questions or vignettes to increase the content of this module or post comments on how we can improve this module for your learning, we look forward to them.

Select how you would like to proceed below:

• Bolognia, J., Cerroni, L., & Schaffer, J. V. (2018). Dermatology.
• Tziotzios, Christos, John Y.w. Lee, Timothy Brier, Ryo Saito, Chao-Kai Hsu, Kapil Bhargava, Catherine M. Stefanato, David A. Fenton, and John A. McGrath. “Lichen Planus and Lichenoid Dermatoses: Clinical Overview and Molecular Basis.” Journal of the American Academy of Dermatology, vol. 79, no. 5 (November 2018): 789-804. https://doi.org/10.1016/j.jaad.2018.02.010.
• Tziotzios, Christos, John Y.w. Lee, Timothy Brier, Ryo Saito, Chao-Kai Hsu, Kapil Bhargava, Catherine M. Stefanato, David A. Fenton, and John A. McGrath. “Lichen Planus and Lichenoid Dermatoses: Conventional and Emerging Therapeutic Strategies.” Journal of the American Academy of Dermatology, vol. 79, no. 5 (November 2018): 807-818. https://doi.org/10.1016/j.jaad.2018.02.0103.
• Lavanya, N., Jayanthi, P., Rao, U. K., & Ranganathan, K. (2011). Oral lichen planus: An update on pathogenesis and treatment. Journal of oral and maxillofacial pathology : JOMFP, 15(2), 127–132. https://doi.org/10.4103/0973-029X.84474
• Weston, G., & Payette, M. (2015). Update on lichen planus and its clinical variants. International journal of women’s dermatology, 1(3), 140–149. https://doi.org/10.1016/j.ijwd.2015.04.001