Lichen planus

Abstract

Lichen planus is a chronic, T-cell-mediated, inflammatory disease of the skin and mucous membranes. Its classic presentation is as violaceous, flat-topped macules and papules, which favour the extremities and flexor creases. When considering the diagnosis of lichen planus, take a thorough drug history to determine whether there is an underlying drug cause before diagnosing ‘idiopathic’ lichen planus. Mucosal surfaces and nails should also be examined in all patients, as the disease commonly also affects these sites. This article explores the clinical presentation, investigations and management of this condition from a primary care perspective.

The GP curriculum and lichen planus

Clinical module 3.21: Care of people with skin problems requires GPs to:

Recognise the importance of skin-specific symptoms e.g. itching and rash distribution

Appreciate the importance of the social and psychological impact of skin problems on the patients’ quality of life (sleep, disfigurement, messy treatment regimens, etc.)

Recognise the spectrum of patterns and distributions of rashes of different skin disorders

Understand how to carry out more detailed tests where indicated, including skin scrapings and the use of Wood’s light

Be prepared to carry out appropriate examination of the skin, including:

^ Addressing the need to undress the patient sufficiently, but with sensitivity to dignity

^ Difficult areas, such as the flexures, genitalia and mucous membranes

Epidemiology

Lichen planus is a relatively common skin condition, affecting 0.2–1% of the adult population (British Association of Dermatologists (BAD), 2016). It can occur at any age, but is more common in adults over 40 years old. It shows little geographical variation, and affects more women than men in a ratio of 3:2. In 50% of cases, it is associated with oral lichen planus, and in 10% of cases there is nail involvement (DermNet New Zealand (NZ), 2015).

Pathogenesis

Lichen planus is a T-cell-mediated autoimmune reaction with clinical and anecdotal evidence pointing to a variety of possible antigen triggers, e.g. viruses, contact allergens and drugs. Studies have pointed to a relationship between Hepatitis B or C and the development of lichen planus (De Carli et al., 2016), although this appears to only be in certain populations. Contact allergens, such as mercury, copper and gold, have also been reported to be problematic (McParland & Warnakulasuriya, 2012). There appears to be a genetic predisposition, and an increased prevalence of lichen planus has been observed in individuals with HLA-DQB1, as well as other haplotypes (Liu et al., 2016). It is also thought that flares of the condition can be triggered by physical or emotional stress.

Clinical features

Cutaneous lichen planus

The most common form of lichen planus is cutaneous lichen planus. This typically presents with the ‘Six Ps’: purple, polygonal, pruritic, planar (flat-topped) papules and plaques. Lesions most often occur on the flexor aspect of the wrists, back and ankles, as shown in Fig. 1, although they can occur anywhere. The lesions are shiny, firm to palpation and range in size from millimetres to greater than a centimetre. The plaques can be laced with fine white lines, called Wickham striae, which can also be found on oral mucosae. Although commonly described as violaceous, the colour is dependent on the skin type of the patient, age of the lesion and location. The classic presentation of new papules or plaques tends to be violaceous in colour; on the palms and soles these can be yellow (hyperkeratosis). After lesions have resolved, there can be residual post-inflammatory hyperpigmentation, which can be a range of shades of brown depending on ethnicity. Lichen planus is among the group of skin conditions that show the Koebner phenomenon: active lesions may arise in sites of previous trauma, including scars and tattoos (DermNet NZ, 2015).

Figure 1.

Classic cutaneous lichen planus.

Oral lichen planus

Around 50% of patients with cutaneous lichen planus will have oral lesions. This appears to be more common in females (DermNet NZ, 2015). It is therefore essential that a thorough oral examination is conducted on a patient with suspected lichen planus. These lesions typically affect the sides of the tongue and buccal mucosae, but all of the oral cavity can be involved, including the lips. Lesions are typically symmetric, so both sides of the oral cavity should be examined. The classic appearance is of Wickham striae (laced white lines) on the side of the tongue, as shown in Fig. 2. Other patterns include persistent ulceration (erosive lichen planus) and erythema and peeling of the gums (desquamative gingivitis).

Figure 2.

Wickham striae in oral lichen planus

Nail lichen planus

Lichen planus can thin the nails and cause the formation of longitudinal grooves and ridges on the surface, as shown in Fig. 3. Onycholyis can occur, as well as scarring of the cuticle (pterygium): in severe cases, the nail can stop growing and disappear (anonychia). These patterns usually occur in combination with cutaneous or oral lichen planus, but can occasionally be the only manifestation of the disease.

Figure 3.

Ridging of the nail in lichen planus.

Lichen planus pigmentosus

Lichen planus pigmentosus is a rare form of lichen planus, which often affects areas of skin that are exposed to the sun, or where two areas of skin rub together, e.g. axilla and groin. However, any part of the body can be affected. The lesions are oval or irregular-shaped brown-grey macules and patches. Patients can develop longstanding macular, greyish hyperpigmentation, but inflammation is minimal.

Case study 1.

An Asian gentleman in his fifties was referred by his GP to secondary care with a 6-month history of a rash comprised of well-demarcated, pigmented macules. The lesions started off on the back and spread to the axilla and arms. Initially these were quite itchy, although this resolved with a very potent topical steroid prescribed by his GP. He could not recall any triggers around the time the lesions appeared. He had no personal or family history of skin problems and the only medical history of note was of type 2 diabetes. The lesions are shown in Fig. 4.

Figure 4.

Axilla of patient with lichen planus pigmentosus.

When seen in secondary care, it was thought this was likely lichen planus pigmentosus and a biopsy was arranged, which confirmed the diagnosis. The patient continued using a super-potent topical steroid and regular emollient for moisturising and washing.

On review in clinic 8 weeks later, the itch had improved significantly. Information and reassurance about the chronic, but benign, nature of the condition was given with advice on the future use of topical steroid therapy should symptoms return.

Vulval lichen planus

Lichen planus can affect the labia minora, labia majora and vagina. The lesions can present in a variety of ways, including: the typical fine white lace-like pattern (usually painless); erosive pattern with ulceration; scarring from previous erosions resulting in adhesions; or desquamative vaginitis. Patients may report pain on urination and sexual intercourse. There is an overlap between the symptoms and appearance with vulval lichen sclerosus. Differentiating the two can be difficult, but lichen planus often affects other mucous membranes, whereas lichen sclerosus rarely does so. A vulval biopsy in secondary care can help distinguish the two if there is clinical uncertainty.

Penile lichen planus

Penile lichen planus usually presents with lesions similar to classic cutaneous lichen planus around the glans, sometimes in a ring formation. Erosive genital lichen planus is less common in men than women (DermNet NZ, 2015), but can cause red, raw and tender lesions around the glans.

Lichen planopilaris

Patchy inflammation can occur around the hair follicles, mainly affecting the scalp. This leads to destruction of the hair follicles and a scarring alopecia. Lone hairs in the areas of baldness are typical of lichen planopilaris (see Fig. 5).

Figure 5.

Lichen planus planopilaris.

Differential diagnosis

The initial important distinction when faced with a rash that clinically looks ‘lichenoid’ is between ‘idiopathic’ lichen planus and a lichenoid drug reaction. These can be difficult to distinguish clinically and histologically (Lukács, Schliemann, & Elsner, 2015), but some differences do exist. Lichenoid drug eruptions can affect sun-exposed areas, may be scalier or have an eczematous/ psoriasiform appearance. A detailed medication history is essential. Common culprits include gold, captopril and hydroxychloroquine. If isolated patches of oral lichen planus occur, consider contact allergy to metal fillings: referral for patch testing to the relevant metals should be considered.

Other conditions to consider in the differential diagnosis include lupus erythematosus, lichen nitidus, lichen striatus, lichen sclerosus, pityriasis rosea and psoriasis. Clinically, discoid lupus erythematosus can be difficult to distinguish, particularly if it only affects the scalp: in this case, scalp biopsies may be helpful. A careful history and examination is essential.

Investigations

In primary care, diagnosis is usually made clinically. Clinical photography can be useful to track new and evolving lesions over time and to monitor response to treatment. If there is any doubt about the diagnosis, then a referral should be made for a 4-mm punch biopsy or an incisional diagnostic biopsy for histopathology.

Management

The disease is usually self-limiting. Asymptomatic lichen planus does not require treatment, although often the rash is itchy.

Primary care

The mainstay of treatment is potent or super-potent topical steroid ointment to reduce inflammation and itch. Typically, this can be betamethasone valerate 0.1% ointment or clobetasol proprionate 0.05% ointment applied once a day to the affected area for 2 to 6 weeks, with review after this (BMJ Best Practice, 2016). Anti-histamines can be added to help break the itch–scratch cycle. Consider a sedating anti-histamine before bed if the itch is keeping the patient up at night, e.g. 4-mg chlorphenamine maleate. If the lesions are persistent or very thick (e.g. hypertrophic lichen planus on the lower legs), consider using an occlusive dressing (such as cling film) over a topical steroid. An example regimen would be clobetasol proprionate 0.05% ointment once a day, then wrapping the affected area with cling film, to be repeated every day for 2 weeks.

The aim when treating oral lesions is symptomatic relief. Patients should also be counselled about conservative measures, such as eating softer foods and avoiding particularly spicy or acidic foods and alcohol, as these can irritate oral lichen planus. Useful agents to consider are benzydamine-based mouth rinse, topical lidocaine or sodium hyaluronate gel. Oral betamethasone mouthwashes twice daily can help (Olson, Rogers, & Bruce, 2016).

The first line treatment for both vulval lichen planus and lichen sclerosus is explanation of the disease, including its chronic nature; use of an emollient and topical steroid. A typical regime for vulval lichen planus would be treatment with betamethasone valerate 0.1% ointment twice daily for 4 to 6 weeks, with application of the ointment when required subsequently. A super-potent topical steroid, such as clobetasol proprionate 0.05% ointment, is the treatment of choice for lichen sclerosus (McPherson & Cooper, 2010).

Patients who are not responding to potent topical steroids, have aggressive lichen planus, hard-to-control itch, multiple sites of mucosal involvement, evidence of scarring or ulceration, or where there is diagnostic uncertainty, should be referred to secondary care.

If you suspect a patient may require immunosuppressive agents via secondary care, it may be helpful to arrange baseline blood tests. These may include a full blood count, liver function tests, renal function and fasting lipids.

Secondary care

If topical agents are unable to control symptoms, then there are a number of oral therapies that can be tried. For very symptomatic disease, a short course of oral prednisolone can help, although patients may experience a rebound flare on stopping. There is evidence to support the use of low-dose acitretin (Atzmony, Reiter, Hodak, Gdalevich, & Mimouni, 2016) to maintain remission, and other agents, including methotrexate and ciclosporin, can be used on a case-by-case basis. Phototherapy in the form of narrowband ultraviolet light-B (Gambichler, Breuckmann, Boms, Altmeyer, & Kreuter, 2005) or psoralen with ultraviolet light-A (Alsenaid, Alamri, Prinz, Ruzicka, & Wolf, 2016) can be used as a monotherapy or as an adjuvant therapy in difficult to treat cases. Similarly, if oral lesions are hard to control, ulcerated or the patient is very symptomatic, systemic treatments can be trialled (Lajevardi et al., 2016).

Complications

If erosive lichen planus has been longstanding, there is a risk this can transform to a squamous cell carcinoma (Knackstedt, Collins, Li, Yan, & Samie, 2015). At-risk areas are mucosal sites, e.g. oral mucosa, vulva and penis (see Fig. 6). Although the exact extent of this risk is not known, some studies have estimated it at between 2 and 5% for vulval lesions (McPherson & Cooper, 2010). Other risk factors for this transformation include smoking history, other malignancies and carrier of human papillomavirus. If an ulcer is slow to heal (e.g. lasting longer than 3 weeks in the oral cavity), not responding to treatment, becoming nodular or thickened, then a 2-week-wait referral should be sent to oral medicine, dermatology or gynae-urology. The referral criteria for suspected cancer are outlined in Box 1.

Figure 6.

Oral squamous cell carcinoma.

Box 1.

NICE Suspected cancer: Recognition and referral guidelines.

1.8 Head and neck cancer

Oral cancer:

1.8.2 Consider a suspected cancer pathway referral (for an appointment within 2 weeks) for oral cancer in people with either:

• Unexplained ulceration in the oral cavity lasting for more than 3 weeks or • A persistent and unexplained lump in the neck

1.8.3 Consider an urgent referral (for an appointment within 2 weeks) for assessment for possible oral cancer by a dentist in people who have either:

• A lump on the lip or in the oral cavity or • A red or red and white patch in the oral cavity consistent with erythroplakia or erythroleukoplakia

1.8.4 Consider a suspected cancer pathway referral by the dentist (for an appointment within 2 weeks) for oral cancer in people when assessed by a dentist as having either:

• A lump on the lip or in the oral cavity consistent with oral cancer or • A red or red and white patch in the oral cavity consistent with erythroplakia or erythroleukoplakia

1.5 Gynaecological cancers

Vulval cancer:

1.5.14 Consider a suspected cancer pathway referral (for an appointment within 2 weeks for vulval cancer in women with an unexplained vulval lump, ulceration or bleeding

Vaginal cancer:

1.5.15 Consider a suspected cancer pathway referral (for an appointment within 2 weeks) for vaginal cancer in women with an unexplained palpable mass in or at the entrance to the vagina

National Institute for Health and Care Excellence (2015) NG12 Suspected cancer: recognition and referral. Manchester: NICE. Available from www.nice.org.uk/ng12 . Reproduced with permission. The information was correct at the date of publication.

Prognosis

Patients should be counselled in relation to the chronic nature of the condition and informed that their condition may be relapsing/ remitting in nature. For some patients the condition will spontaneously regress after 18 months, but for many it may last longer. Treatment should be centred on symptomatic relief. Clinicians should remain vigilant for evolving mucosal lesions and have a low threshold for referral in the case of suspected squamous cell carcinoma.

Key points

Be aware of lichen planus as a differential diagnosis for an itchy rash

The classic presentation of lichen planus is as the ‘6 Ps’ – purple, polygonal, pruritic, planar papules and plaques, but remember there are other, rarer forms

When lichen planus is suspected, a thorough examination of the oral cavity, nails, scalp and full skin examination should be performed

Patients who are unresponsive to potent topical steroids, have aggressive lichen planus, severe itch, evidence of scarring/ ulceration or where there is diagnostic uncertainty, should be referred to secondary care

Potent and super-potent topical steroids are the mainstay of treatment and this should be initiated in primary care

Longstanding mucosal lichen planus has a malignant potential; clinicians should be vigilant of this and refer urgently to secondary care if concerned

References

Alsenaid

Alamri

Prinz

J. C.

Ruzicka

Wolf

(2016) Lichen planus of the lower limbs: Successful treatment with psoralen cream plus ultraviolet A photochemotherapy. Dermatologic Therapy 29(2): 109–113. doi: 10.1111/dth.12321.

Atzmony

Reiter

Hodak

Gdalevich

Mimouni

(2016) Treatments for cutaneous lichen planus: A systematic review and meta-analysis. American Journal of Clinical Dermatology 17(1): 11–22. doi: 10.1007/s40257-015-0160-6.

BAD. (2016). Patient information leaflet: Lichen planus. Retrieved from www.bad.org.uk/shared/get-file.ashx?id=168&itemtype=document.

BMJ Best Practice. (2016). Lichen planus. Retrieved from http://bestpractice.bmj.com/best-practice/monograph/624/treatment/step-by-step.html.

De Carli

J. P.

Linden

M. S.

da Silva

S. O.

Trentin

M. S.

Matos

F. D. S.

Paranhos

L. R.

(2016) Hepatitis C and oral lichen planus: Evaluation of their correlation and risk factors in a longitudinal clinical study. The Journal of Contemporary Dental Practice 17(1): 27–31.

DermNet NZ. (2015). Lichen planus. Retrieved from www.dermnetnz.org/scaly/lichen-planus.html.

Gambichler

Breuckmann

Boms

Altmeyer

Kreuter

(2005) Narrowband UVB phototherapy in skin conditions beyond psoriasis. Journal of the American Academy of Dermatology 52(4): 660–670. doi: 10.1016/j.jaad.2004.08.047.

Knackstedt

T. J.

Collins

L. K.

Yan

Samie

F. H.

(2015) Squamous cell carcinoma arising in hypertrophic lichen planus: A review and analysis of 38 cases. Dermatologic Surgery 41(12): 1411–1418. doi: 10.1097/DSS.0000000000000565.

Lajevardi

Ghodsi

S. Z.

Hallaji

Shafiei

Aghazadeh

Akbari

(2016) Treatment of erosive oral lichen planus with methotrexate. Journal der Deutschen Dermatologischen Gesellschaft 14(3): 286–293. doi: 10.1111/ddg.12636.

10.

Liu

Mayer

J. G.

Hoch

B. A.

Green

Rolak

Hebbring

S. J.

(2016) Phenome-wide association study maps new diseases to the human major histocompatibility complex region. Journal of Medical Genetics 53(10): 681–689. doi:10.1136/jmedgenet-2016-103867.

11.

Lukács

Schliemann

Elsner

(2015) Lichen planus and lichenoid reactions as a systemic disease. Clinics in Dermatology 33(5): 512–519. doi: 10.1016/j.clindermatol.2015.05.001.

12.

McParland

Warnakulasuriya

(2012) Oral lichenoid contact lesions to mercury and dental amalgam–a review. Journal of Biomedicine and Biotechnology 2012: 589–569. doi: 10.1155/2012/589569.

13.

McPherson

Cooper

(2010) Vulval lichen sclerosus and lichen planus. Dermatologic Therapy 23(5): 523–532. doi: 10.1111/j.1529-8019.2010.01355.x.

14.

NICE. (2015). Suspected cancer: Recognition and referral. Retrieved from www.nice.org.uk/guidance/ng12/chapter/1-recommendations-organised-by-site-of-cancer#head-and-neck-cancers.

15.

Olson

M. A.

Rogers

R. S.

Bruce

A. J.

(2016) Oral lichen planus. Clinics in Dermatology 34(4): 495–504. doi: 10.1016/j.clindermatol.2016.02.023.

16.

RCGP. Clinical module 3.21: Care of people with skin problems. Retrieved from www.rcgp.org.uk/training-exams/gp-curriculum-overview/online-curriculum/applying-clinical-knowledge-section-2/3-21-skin-problems/3-21-knowledge-and-skills.aspx.