Flat-topped, slightly violaceous papules - MPR

Flat-topped, slightly violaceous papules

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  • Lichen Planus 1_0312 Derm Dx

  • Lichen Planus 2_0312 Derm Dx

  • Lichen Planus 3_0312 Derm Dx

  • Lichen Planus 4_0312 Derm Dx

A 50-year-old otherwise healthy black male presents complaining of itchy papules that have been present for several months. He denies any preceding illnesses or medication changes. Besides extreme pruritis, his review of symptoms is negative.

Past medical history is unremarkable. Family history is noncontributory. He was seen recently at an urgent care clinic and prescribed triamcinolone 0.1% ointment that provided only minimal relief. On exam, he is a healthy appearing black male with normal vital signs.

Physical exam is significant for annular and polygonal, flat-topped, slightly violaceous papules on the trunk and extremities. Some of the annular lesions have a slightly atrophic center. Other lesions appear excoriated. There are no lesions on his mouth, genitalia or nails. What’s your diagnosis?

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Lichen planus is an idiopathic inflammatory disease that may affect the skin, nails, hair and mucous membranes. In the classic cutaneous form, there is an eruption of flat-topped, pruritic, violaceous papules favoring the volar wrists and forearms, genitals, shins and...

Submit your diagnosis to see full explanation.

Lichen planus is an idiopathic inflammatory disease that may affect the skin, nails, hair and mucous membranes. In the classic cutaneous form, there is an eruption of flat-topped, pruritic, violaceous papules favoring the volar wrists and forearms, genitals, shins and lower back. 

There are multiple clinical variants of lichen planus including hypertrophic, drug-induced and lichen planopilaris, which affects the hair and causes a scarring alopecia. Additionally, certain variants favor exclusively mucosal surfaces, a complete discussion of which is outside the scope of this case presentation.

This patient presented with classic cutaneous disease consisting of the five Ps: pruritic, planar, purple, polygonal papules. The annular lesions are round in shape with a slightly raised edge and an atrophic center.1, 2

Oral involvement occurs in as many as 75% of patients with cutaneous disease, most commonly affecting the buccal mucosa. Oral lesions can be reticular (whitish and netlike), erosive or erythematous. Ulcerative and erythematous oral lichen planus is associated with an approximate 1% to 2% risk of developing oral squamous cell carcinoma. Lesions on the genitalia may also be ulcerative. Up to 3% of patients with erosive vulvar lichen planus are at risk for developing squamous cell carcinoma.1, 2

Nail involvement occurs in only 10% of patients with cutaneous disease and frequently consists of sandpaper-like thinning of the nails and/or dorsal nail pterygium. 

Although idiopathic lichen planus may be indistinguishable from a lichenoid drug reaction, lichenoid drug reactions are less likely to involve mucosal surfaces and more likely to be photo distributed. A biopsy may be helpful (described below). 

Lichenoid drug reactions are caused by many drugs, most notably hydrochlorothiazide, captopril, enalapril, labetalol, methyldopa and propranolol.  Importantly, there may be a latent period ranging from weeks to years prior to rash onset.

Diagnosis                       

The diagnosis is based on classic physical exam findings and is reinforced with biopsy. The histological features include a band-like infiltrate of lymphocytes at the dermal-epidermal junction, saw-tooth acanthosis and wedge-shaped hypergranulosis. The presence of eosinophils and parakeratosis may favor a lichenoid drug reaction. 1, 2                  

Treatment and prognosis           

Classic cutaneous lichen planus is a self-limited disease and generally resolves within one to two years without treatment. Oral mucosal disease is more refractory to treatment, and the ulcerative variant almost never spontaneously resolves. 

Therapy for all variants may include oral, topical or intralesional corticosteroids, topical tacrolimus or pimecrolimus, systemic retinoids, phototherapy and systemic immunosuppressants, such as cyclosporine or mycophenolate mofetil. 

There are numerous other topical and systemic therapies that have been attempted with variable success. Treatment decisions are based on the extent of the disease and its impact on the patient’s quality of life. 1, 2                      

Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine in Houston.

References

1. Bolognia J, Jorizzo JL, Rapini RP. “Chapter 12: Lichen Planus and Lichenoid Dermatosis.” Dermatology. 2008; Mosby/Elsevier; St. Louis, Mo.

2. James WD, Berger TG, Elston DM et al. “Chapter 12: Lichen Planus and Related Conditions.” Andrews’ Diseases of the Skin: Clinical Dermatology. 2006; Saunders Elsevier: Philadelphia.