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Dermatology Diagnosis

When A Patient Presents With Pruritic Papules And Plaques

A 58-year-old man presented with chronic recurrent onychocryptosis and a rash on his right leg. The patient felt his rash was due to his history of venous insufficiency. He had tried wearing support stockings every day but the rash has persisted and become quite itchy. According to the patient, the pruritus subsides at times but then recurs.

The patient denies any rashes or sores elsewhere. He also denies symptoms of hay fever or asthma. His blood pressure is moderately elevated at 148/88 and he is afebrile. His past medical history includes obesity and controlled hypertension, hyperuricemia and type 2 diabetes. Medications include lisinopril, allopurinol and metformin.

The physical examination reveals multiple deeply incurvated but otherwise normal pedal nails. There is a 20 by 10 cm plaque on the right leg. He reports the pruritic rash started insidiously four months before and has gradually enlarged and thickened despite the patient using a variety of antifungal creams and over-the-counter emollients.

Key Questions To Consider

1. What is this condition?
2. What is the differential diagnosis?
3. What are the key characteristics of this condition?
4. What is the most effective treatment?

Answering The Key Diagnostic Questions

1. Lichen planus
2. Venous stasis dermatitis with atrophie blanche, lipodermatosclerosis, pyoderma, psoriasis, lichen nitidus, pityriasis rosea, pityriasis rubra pilaris
3. Wickham’s striae are the most important indicator. Lichen planus also presents with pathognomonic, severely pruritic, polygonal, violaceous, flat-topped papules and plaques.
4. Treatment options include high-potency corticosteroids like halobetasol propionate ointment or topical triamcinolone ointment.

Pertinent Considerations With The Differential Diagnosis

Venous stasis dermatitis with atrophie blanche should be a top consideration but the anterior middle tibial location of the affected area is above the gaiter area and not centered over a deep perforating vein, making this differential diagnosis less likely.

There is accompanying subcutaneous fibrosis and atrophy in our patient, as shown in the second photo. This loss of limb contour resembles lipodermatosclerosis, which often accompanies venous disease, but venous disease is typically bilaterally symmetrical and circumferential. Lipodermatosclerosis is a sclerosing panniculitis that binds the skin to the underlying subcutaneous tissue. It is often a chronic and painful process affecting both lower legs, and is caused by chronic venous hypertension.1

Pyoderma is another differential to consider. However, a cutaneous bacterial infection ought to have some erythema, heat or drainage, and the patient’s rash is hyperpigmented, warm and dry. The patient does not exhibit lower extremity hair so a furuncle is also less likely. The patient does complain of significant pruritus so one should consider neurodermatitis or atopic eczema, but he is not scratching. The patient also denies a history of sensitive skin or allergies. The thickening and exaggeration of skin creases of the lichenification of lichen simplex chronicus is not apparent.

Psoriasis should be close to the top of the differential diagnosis list but the patient’s scalp and other body areas are clear. Also, there is relative lack of erythema and scale formation within the plaque, which is more characteristic of psoriasis.

Dockery and Bakotic have suggested additional differentials of lichen planus including lichen nitidus, pityriasis rosea, pityriasis rubra pilaris and warts.2

Lichen nitidus is a chronic inflammatory disease characterized by minute, shiny, flat-topped, pale, discrete papules, and primarily occurs in children or young adults. Lichen nitidus is harmless and typically clears spontaneously within a year. The palms and soles can be involved in lichen nitidus with keratotic plugs within hyperkeratotic plaques, helping to differentiate it from lichen planus. Actually, lichen nitidus used to be considered a variant of lichen planus but it is now treated as an unrelated condition.3

Pityriasis rosea is a mild inflammatory viral exanthem characterized by salmon-colored macules and papules that initially are small and discrete but develop into confluent plaques. The lesions contain human herpesvirus types 6 and 7. Initially a large distinctive erythematous herald patch presents. Then as the lesions desquamate, they exhibit a characteristic collarette of scale. The long axes of the macules are in a parallel arrangement and distributed along the lines of skin cleavage. Pityriasis rosea lesions are typically generalized and rarely affect the lower legs and soles.4

Pityriasis rubra pilaris may present on the extensor surfaces of limbs as yellowish scaling patches with a solid confluent hyperkeratotic sandal. The patient’s soles are clear. In addition, the characteristic lesions of pityriasis rubra pilaris are small follicular papules with horny plugs. Researchers believe pityriasis rubra pilaris is a vitamin A deficiency.4

Collecting scales for immediate light microscopy or periodic acid Schiff (PAS) staining would go a long way to rule out dermatophytosis. In my experience, perhaps 20 percent of our patients are fungus friendly, being genetically susceptible to dermatophytes, so careful inspection of the soles and toe webs for concurrent tinea is important. One can use glass microscope slides to safely scrape the surface of the lesion or collect scales with transparent tape.

Practical Keys To Diagnosing Lichen Planus

Cutaneous lichen planus is a chronic autoimmune inflammatory disease that classically presents with pathognomonic, severely pruritic, polygonal, violaceous, flat-topped papules and plaques.5,6 This classical polyp presentation clearly helps to make the diagnosis. Initially, the papules are erythematous and over time become violaceous and eventually hyperpigmented.3 It helps to notice the pattern of papules that vary in size and shape while coalescing into palpable plaques.

The most important clue is detecting Wickham’s striae. Wickham’s striae are gray to white streaks atop the papules. A dermoscopy examination is helpful in detecting this diagnostic sign.3,6

Intense pruritus typically begins even before the lesions appear. Lichen planus has a predilection for the wrist flexors, trunk, thighs, shins and glans penis. The palms and soles may develop small papules or hyperkeratotic plaques.3,6 Simple examination of the tongue and buccal mucosa may detect the distinctive lacy white network characteristic of lichen planus.7

Thankfully, a minority of patients develop concurrent nail changes that can be quite destructive. The nail unit inflammatory process of lichen planus causes the proximal nail fold to scar and form a wing-like overgrowth called dorsal pterygium. The nail plate can become longitudinally ridged and split, creating onychorrhexis.3

What Causes Lichen Planus?

The pathogenesis of lichen planus is, in theory, the activation of T lymphocytes that are recruited to the dermal–epidermal junction, inducing apoptosis in the basal keratinocytes.8 Although there is a significant statistical association between the hepatitis C virus and lichen planus, researchers have not established a direct cause and effect relationship.8,9  

A wide variety of drugs may induce lichen planus. The list includes many of the drugs our patients are exposed to including: tetracyclines, ibuprofen, naproxen, anti-hypertensives, allopurinol and griseofulvin.10 There also have been reports of an association between lichen planus and the administration of hepatitis B and inactivated influenza vaccinations.8 Case reports have also documented lichen planus arising in tattoos of various pigments.8

Although there are multiple clinical variants of lichen planus that may differ based on the site of occurrence and the predominant lesion, all the variants of lichen planus share the same basic histological features.6 The lower leg varieties are either bullous lichen planus or hypertrophic lichen planus, characterized by the development of intensely pruritic, flat-topped plaques, as demonstrated in the aforementioned patient.7

It is common practice to diagnose cutaneous lichen planus based upon the recognition of consistent clinical findings. In cases in which the diagnosis is uncertain or the patient fails to respond to therapy, a biopsy would capture the distinctive histology of lichen planus. A simple punch or shave biopsy that at least reaches the mid-dermis should confirm the diagnosis. The distinctive pathologic findings are a band-like lymphocytic infiltrate, saw-tooth rete ridges, multiple apoptotic keratinocytes and wedge-shaped hypergranulosis.6

In lichen planus, dermoscopy increases the accuracy of the clinical diagnosis, helps avoid skin biopsies and objectively tracks therapeutic progress. The dermoscopic diagnosis is based on recognizing three distinctive patterns. Looking for the diagnostic thin white crossing reticular streaks of Wickham’s striae is key. Also, a red dotted vascular pattern is characteristic. Pigmented dots, globules and diffuse hyperpigmentation are additional dermoscopic markers for the melanocytic proliferation of lichen planus.11

A Closer Look At The Treatment Options

Fortunately, over time, lichen planus clears on its own in many patients. However, active treatment is indicated to help control cases of severe pruritus and help to speed up resolution. First-line therapy centers on topical corticosteroids for localized lesions and phototherapy for more generalized disease. High-potency corticosteroids like halobetasol propionate (Ultravate, Sun Pharmaceutical Laboratories) ointment applied twice daily are appropriate for initial treatment of foot and leg lesions. Hypertrophic lesions may need intralesional injections of triamcinolone. If necessary, one could consider a repeat injection in six weeks.8

Any use of corticosteroid therapy naturally needs monitoring for potential side effects of unwanted atrophy, striae or hypopigmentation. Periodic monitoring is important because of the occasional development of cutaneous squamous cell carcinoma that researchers have reported in patients with longstanding hypertrophic lichen planus lesions.6

Thankfully, the majority of patients clear within one year but this may not be soon enough for the patient and the doctor. Unfortunately, recurrences are too common.

Atzmony and colleagues have compared lichen planus treatments in a comprehensive meta-analysis.12 The authors found responses to acitretin (Soriatane, Stiefel Laboratories), sulfasalazine (Azulfidine, Pfizer) and griseofulvin were equivalent to placebo therapy. The reviewed studies also demonstrated that ultraviolet B radiation was more effective than six weeks of low-dose prednisolone. Additionally, prednisolone was more effective than enoxaparin in achieving complete response and betamethasone valerate 0.1% ointment had comparable efficacy to a calcipotriene ointment.

In Summary

Our patient has the distinctive pruritic, polygonal papules and plaques with white lacy striae, diagnosed as hypertrophic lichen planus. Although his lesions have failed to completely resolve, the intermittent use of topical triamcinolone ointment controls his symptoms.

Dr. Bodman is a retired Associate Professor with the Kent State University College of Podiatric Medicine. He is board-certified by the American Board of Podiatric Medicine.

References

1.     Choonhakarn C, Chaowattanapanit S, Julanon N. Lipodermatosclerosis: a clinicopathologic correlation. Int J Dermatol. 2016;55(3):303-8.
2.     Dockery GD, Bakotic B. What you should know about lichen planus. Podiatry Today. 2007; 20(6):52–60.
3.     James WD, Elston DM, Berger TG, Andrews GC. Lichen planus and related conditions. In Andrews’ Diseases of the Skin: Clinical Dermatology, Chapter 12. Saunders/Elsevier, London, 2011, p. 213–18.
4.     James WD, Elston DM, Berger TG, Andrews GC. Pityriasis rosea, pityriasis, rubra pilaris, and other papulosquamous and hyperkeratotic diseases. In Andrews’ Diseases of the Skin: Clinical Dermatology, Chapter 11. Saunders/Elsevier, London, 2011, p. 204–5.  
5.     Puza C, Cardones AR. Concepts and controversies in the treatment of cutaneous lichen planus. G Ital Dermatol Venereol. 2017;152(6):607-614.
6.     Goldstein BG, Goldstein AO, Mostow E. Lichen planus. UpToDate. Available at https://www.uptodate.com/contents/lichen-planus . Published June 27, 2017.
7.     Wagner G, Rose C, Sachse MM. Clinical variants of lichen planus. J Dtsch Dermatol Ges. 2013;11(4):309-19.
8.     Lehman JS, Tollefson MM, Gibson LE. Lichen planus. Int J Dermatol. 2009;48(7):682.
9.     Shengyuan L, Songpo Y, Wen W, Wenjing T, Haitao Z, Binyou W. Hepatitis C virus and lichen planus: a reciprocal association determined by a meta-analysis. Arch Dermatol. 2009;145(9):1040.
10.     Bork K. Lichenoid eruptions. In: Bork K (ed.), Cutaneous Side Effects of Drugs. WB Saunders, Philadelphia, 1988, p. 170.
11.     Ianoși SL, Forsea AM, Lupu M, Ilie MA, Zurac S, Boda D, Ianosi G, Neagoe D, Tutunaru C, Popa CM, Caruntu C. Role of modern imaging techniques for the in vivo diagnosis of lichen planus. Exp Ther Med. 2019;17(2):1052-1060.
12.     Atzmony L, Reiter O, Hodak E, Gdalevich M, Mimouni D. Treatments for cutaneous lichen planus: a systematic review and meta-analysis. Am J Clin Dermatol. 2016;17(1):11-22.

Dermatology Diagnosis
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By Myron Bodman, DPM
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