Derm Dx: Brown, Irregular, Nonblanching Plaques - Dermatology Advisor

Derm Dx: Brown, Irregular, Nonblanching Plaques

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A 42-year-old man presents to a local dermatology clinic with a rash on his right thigh. He first noticed the rash approximately 4 months earlier. The rash originally had a red color but was completely asymptomatic. The patient reports being otherwise healthy. He denies taking any medications. He has never had a similar rash in the past. On examination, multiple brown, irregular, nonblanching plaques are noted on the patient’s right upper leg. On dermoscopy, multiple tiny red puncta are seen within the plaques.

Pigmented purpuric dermatoses (PPD) are a group of chronic, relapsing skin conditions that typically present with symmetrical bronze discoloration, petechiae, and pigmented macules on the lower extremities.1-3 There are 5 main subcategories of PPD based on varying clinical presentation: progressive...

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Pigmented purpuric dermatoses (PPD) are a group of chronic, relapsing skin conditions that typically present with symmetrical bronze discoloration, petechiae, and pigmented macules on the lower extremities.1-3 There are 5 main subcategories of PPD based on varying clinical presentation: progressive pigmented purpuric dermatosis (Schamberg disease), purpura annularis telangiectodes (Majocchi disease), lichen aureus, pigmented purpuric lichenoid dermatosis (PPLD) of Gougerot-Blum, and eczematid-like purpura of Doucas-Kapetanakis.1,4 Other rare presentations include itching purpura of Loewenthal, as well as linear, quadrantic, transitory, granulomatous, and familial forms. Although many clinical variants have been described, those with related histopathology are typically managed in a similar manner.1,2 Besides experiencing rash, patients are generally asymptomatic, although some may experience slight itching with Schamberg disease and more severe itching with eczematid-like purpura of Doucas-Kapetanakis.1

Schamberg disease is a chronic, persistent subtype of PPD characterized by orange or brown irregular plaques formed by small reddish puncta. The color occurs as a result of hemosiderin deposition. Although this type of PPD mainly affects the lower limbs, it may occur on any part of the body and may display a slow, proximal extension. Venous insufficiency likely plays a role in localization of this variant. Majocchi disease is associated with bluish-red annular macules and telangiectatic puncta; atrophy of the central area is also frequently identified. Similar to that seen with Schamberg disease, Majocchi disease begins on the lower limbs and may extend to the upper extremities. However, unlike the presentation of Schamberg disease, there is an absence of venous stasis in patients with Majocchi disease. Lichen aureus is more localized and associated with lichenoid papules, intensely purpuric lesions, and golden-brown plaques that may occasionally affect the trunk and face. PPLD of Gougerot-Blum is also characterized by lichenoid papules that convulse to form plaques. This subtype is primarily localized to the legs and is rarely seen on the trunk and thighs. The presentation of eczematid-like purpura of Doucas-Kapetanakis is similar to that of Schamberg disease with extensive lesions; the differentiating characteristic is the severe pruritus that accompanies the lesions in the former. This subtype often spontaneously improves, although recurrences are not uncommon.1

PPD is a rather rare condition in the United States.1,3 Schamberg disease is the most common subtype and has been reported in all age groups.1,3-5 In general, PPD can present in all ages and races, with certain clinical subtypes presenting more frequently in specific age and racial groups. Itching purpura, PPLD, and the granulomatous variant occur predominantly in middle-aged individuals, while lichen aureus and Majocchi disease are more commonly seen in childhood or adolescence.1 Although PPD appears more commonly in men overall,1,3,4 individual clinical variants, such as Majocchi disease, seem to predominantly affect women.1

The etiology of PPD is unknown; however, a number of conditions and drugs have been implicated as cofactors in disease development.1 These conditions include chronic venous hypertension, exercise, capillary fragility, focal infections, chemical ingestion, and gravitational dependency.1 Associations with diabetes mellitus, rheumatoid arthritis, lupus erythematosus, thyroid dysfunction, hereditary spherocytosis, hematologic disorders, hepatic disease, porphyria, malignancies, hyperlipidemia, and hypercholesterolemia have been described.1,3 Although an association between PPD and hepatitis B and C infection had been reported, recent studies have cast doubt on a potential relationship.6 The most notable risk factors for the development of PPD seem to be venous insufficiency and long periods of standing during daily activities.3,4

Histomorphologic examination of PPD reveals superficial CD3+, CD4+, and CDIA+ lymphocytic infiltration, erythrocyte extravasations, and hemosiderin deposition.1,2 Cell-mediated immunity as well as immune complexes have been implicated in disease evolution.1 Clinically, PPD is distinguished based on history, blood counts, biopsy, and if necessary, genetic testing.1,7,8

PPD is most frequently misdiagnosed as vasculitis, thrombocytopenia, or early mycosis fungoides. The differential diagnosis of PPD also includes hyperglobulinemic purpura, purpuric clothing dermatitis, stasis pigmentation, scurvy, leukocytoclastic vasculitis, and drug hypersensitivity reactions.1,5 Thus, a complete blood count and peripheral smear are necessary to rule out thrombocytopenia. Coagulation screen, bleeding time, platelet aggregation, and capillary fragility test help to exclude other causes of purpura. Testing for antinuclear antibodies, rheumatoid factor, anti-HBsAg antibody, and anti-hepatitis C virus antibody aids in excluding a rheumatologic or viral etiology. In PPD, laboratory testing is often unremarkable with occasional target-shaped, tear-drop erythrocytes, anisocytosis, and hypochromia seen on peripheral blood smear.1 Dermatoscopy, which is a diagnostic technique that renders the corneal layer of skin translucent, may assist in visualization of the distinct pattern of petechiae and purpura.5 

Serial biopsies and gene arrangement studies may be necessary to differentiate PPD from mycosis fungoides; a polyclonal T-cell population suggests the former while a monoclonal T-cell population suggests the latter. In many cases, PPD may mimic early mycosis fungoides and is even hypothesized to transform into mycosis fungoides due to their similar etiology of T-cell dyscrasia.7 Widespread involvement of purpuric patches and pruritus lasting longer than a year or atypical pigmented purpuric lesions should prompt further diagnostic measures, including serial biopsies and gene arrangement studies. Clinical picture and history, histology, and gene arrangement studies may aid in the distinction; however, differentiating between the 2 disorders remains a diagnostic limitation as PPD may histologically and/or genetically resemble mycosis fungoides.7,8 

Although many cases of PPD are asymptomatic, the cosmetic effects of the persistent rash can cause significant distress to patients and affect quality of life.9 There is currently no proven medical intervention to treat PPD. Treating the underlying condition or removing the offending agent may be beneficial. The mainstay of treatment is symptom management via topical corticosteroids and antihistamines for pruritus. Leg compression and avoiding long periods of standing are recommended to prevent associated venous stasis.1 Psoralen photochemotherapy has been shown to be successful in treating Schamberg disease, pigmented purpuric dermatosis of Gougerot-Blum, and lichen aureus.1 Narrow-band ultraviolet B phototherapy has also demonstrated efficacy in Schamberg disease and Majocchi purpura.10 Griseofulvin, pentoxifylline, cyclosporine, and a combination of oral rutoside and ascorbic acid have shown encouraging results in small case studies.1

The patient in the case presented elected to undergo treatment with topical triamcinolone. At 1-month follow-up, the skin discoloration remained and had not significantly improved. 

Anna Poliner, BSA is a medical student; Talia Noorily, BA, is a medical student; and Christopher Rizk, MD, is a dermatology fellow at Baylor College of Medicine, Houston, Texas.

References

  1. Sardana K, Sarkar R, Sehgal VN. Pigmented purpuric dermatoses: an overview. Int J Dermatol. 2004;43(7):482-488.
  2. Kim DH, Seo SH, Ahn HH, Kye YC, Choi JE. Characteristics and clinical manifestations of pigmented purpuric dermatosis. Ann Dermatol. 2015;27(4):404-410.
  3. Gönül M, Çakmak SK, Özcan N, Oğuz ID, Gül Ü, Biyikli Z. Clinical and laboratory findings of pigmented purpuric dermatoses. Ann Dermatol. 2014;26(5):610-614.
  4. Sharma L, Gupta S. Clinicoepidemiological study of pigmented purpuric dermatoses. Indian Dermatol Online J. 2012;3(1):17-20.
  5. Ozkaya DB, Emiroglu N, Su O, et al. Dermatoscopic findings of pigmented purpuric dermatosis. An Bras Dermatol. 2016;91(5):584-587.
  6. Ehsani AH, Ghodsi SZ, Nourmohammad-Pour P, Aghazadeh N, Damavandi MR. Pigmented purpura dermatosis and viral hepatitis: a case-control study. Australas J Dermatol. 2013;54(3):225-227.
  7. Riyaz N, Sasidharanpillai S, Abdul Latheef EN, Davul H, Ashraf F. Pigmented purpuric dermatosis or mycosis fungoides: a diagnostic dilemma. Indian Dermatol Online J. 2016;7(3):183-185.
  8. Ladrigan MK, Poligone B. The spectrum of pigmented purpuric dermatosis and mycosis fungoides: atypical T-cell dyscrasia. Cutis. 2014;94(6):297-300.
  9. Plachouri KM, Florou V, Georgiou S. Therapeutic strategies for pigmented purpuric dermatoses: a systematic literature review [published online May 18, 2018]. J Dermatol Treat. https://doi.org/10.1080/09546634.2018.1473553
  10. Fathy H, Abdelgaber S. Treatment of pigmented purpuric dermatoses with narrow-band UVB: a report of six cases. J Eur Acad Dermatol Venereol. 2011;25(5):603-606.
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