A 31-year-old female presented with a burning rash on upper arms, groin, and axillae

Lichen planus (LP) is a chronic, pruritic, inflammatory disease that can affect the skin, hair, nails, and mucosal surfaces. The exact cause is unknown, but possible causes include medications, dental amalgam fillings, or an autoimmune reaction. Drugs implicated in causing LP include beta-blockers, methyldopa, penicillamine, quinidine, and quinine. A meta-analysis of case-control studies show a statistically significant association between hepatitis C infection and LP patients; thus, all patients presenting with LP should be screened for hepatitis.¹ Individuals of all age groups and races can be affected by LP, but it is predominantly observed in middle-aged adults. Women are also twice as likely to get oral lichen planus.²

Atrophic lichen planus, the least common form of LP, presents as flat, violaceous papules with an atrophic, pale center. Although these papules can be found anywhere on the body, they most commonly affect the trunk and/or legs on areas of the skin previously affected by classical lichen planus.³ In most cases, LP is diagnosed by observing its clinical features. A biopsy is recommended to confirm the diagnosis for more atypical cases.

^{Courtesy Alaa Erras, University of California, San Diego, and Brooke Resh Sateesh, MD, San Diego Family Dermatology}

Histopathology reveals thinning of the epidermis with flattening of the rete ridges, vacuolar degeneration of the basal layer, and a lichenoid mononuclear infiltrate in the papillary dermis.

^{Courtesy Alaa Erras, University of California, San Diego, and Brooke Resh Sateesh, MD, San Diego Family Dermatology}

If the patient is diagnosed with LP but experiences no symptoms, treatment is not needed as LP may resolve spontaneously within 1-2 years. Recurrences are common, however. Lesions may heal with hyperpigmentation. Possible treatments that can help relieve symptoms of pruritus are high potency topical corticosteroids, calcineurin inhibitors, and antihistamines. In more severe and widespread cases, lesions may respond well to systemic corticosteroids or intralesional steroid injections.⁴ Phototherapy is reported to be effective as well. Acitretin, isotretinoin, methotrexate, hydroxychloroquine, and mycophenolate mofetil are all described in the literature. It is important to note that LP on mucous membranes may be more persistent and resistant to treatment.¹

Dr. Donna Bilu Martin

In this patient, a punch biopsy was performed, confirming the diagnosis. The patient was treated with topical and intralesional steroids, as well as a course of prednisone, and her lesions improved with treatment. Hepatitis serologies were negative.

This case and photo were submitted by Ms. Erras of the University of California, San Diego, and Dr. Sateesh, of San Diego Family Dermatology, and edited by Donna Bilu Martin, MD.

Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at mdedge.com/dermatology. To submit a case for possible publication, send an email to dermnews@mdedge.com.

References

1. Usatine R, Tinitigan M. Am Fam Physician. 2011 Jul 1;84(1):53-602.

2. Lichen planus, Johns Hopkins Medicine. [Cited 2022 Mar 13.]

3. Atrophic lichen planus, Genetic and Rare Diseases Information Center (GARD) – an NCATS Program. [Cited 2022 Mar 13.]

4. ”Atrophic lichen planus,” Medscape, 2004 Feb 1. [Cited 2022 Mar 13.]