• Most useful hypotheses/associations in clinical practice (not always causal):
  • Localized immunological event mediated by T cells with superficial endothelial damage → erythrocyte extravasation. Smoller 1991
  • Comorbidities/associated medication reported in cohorts (e.g., HTN/DM; use of statins, beta blockers, etc.). Kim Xnumx
  • Local factors (e.g., capillary fragility/stasis/vessel-related variants) suggested in subtypes such as golden lichen. Reinhardt 1983
  • Within a subset, there may exist mimicry with cutaneous T-cell lymphoma (CTCL) (e.g., purpuric/"PPD-like" mycosis fungoides), which necessitates vigilance when the evolution or histology does not fit. Çaytemel 2021, Sun 2023

• Elementary injury
  • Petechiae punctate (“cayenne pepper”) and spots/plaques purple with brownish-gold tone progressive Sardana 2004
•  Most affected areas
  • Predominance in legs/ankles; sometimes thighs; less frequently trunk/upper limbs. Sardana 2004, Kim Xnumx
• prototypical picture
  • insidious beginning of purpuric macules in lower extremities, non-palpable, usually without systemic symptoms; variable pruritus. Spigariolo 2021
• Clinical findings by subtype (indicative)
  • Schamberg: “cayenne pepper” + diffuse ochre pigmentation. Sardana 2004
  • Majocchi: annular/arcuate lesions with telangiectasias. Spigariolo 2021
  • Lichen aureus: plate or plates golden persistent, sometimes along the venous pathway; occasional pain/itching. Reinhardt 1983
  • Gougerot-Blum: purpuric papules/plaques lichenoids. Spigariolo 2021
• Evolution
  • Course chronic (months-years), with relapses; the purpura may subside and remain hyperpigmentation. Sardana 2004
  • In patients pediatrica relevant proportion may resolve spontaneouslyIt is not usually associated with vasculitis/coagulopathy in large cohorts. Ollech 2020, Torrelo 2003
• Atypical presentations (raise concerns and warrant biopsy/re-evaluation)
  • widespread, very itchy, resistant, with infiltration o marked scaling, or with progressive evolution despite management (consider LCCT). Çaytemel 2021, Sun 2023

• Leukocytoclastic vasculitis: purple palpable, pain, necrosis/blisters, systemic symptoms; histology with fibrinoid necrosis/leukocytoclasia (unlike DPP). Huang 2018

• Thrombocytopenic/coagulopathy purpura: More extensive distribution, mucous membranes, bleeding; abnormal laboratory tests. (In placental abruption, labs are typically normal). Torrelo 2003

• Stasis dermatitis: edema, varicose veins, eczema, lipodermatosclerosis; may coexist/overlap clinically. Spigariolo 2021

• Drug-induced purpura/anticoagulants, scurvy, traumatic purpuraClinical/laboratory context provides guidance. Spigariolo 2021

• Purpuric mycosis fungoides (PPD-like): persistent, sometimes disseminated lesions with clinical variability; requires histo-immuno-molecular correlation. Sun 2023, Foo 2007

• Histological pattern
  • Superficial perivascular dermatitis (capillaritis): superficial lymphocytic infiltrate + erythrocyte extravasation + hemosiderin-containing macrophages. Huang 2018, Sardana 2004
• Key findings (practical)
  • Mild reactive endothelium, variable lymphocytic infiltrate; without neither fibrinoid necrosis nor dense neutrophilic infiltrate typical of vasculitis. Huang 2018
  •  Variants:
    • Lichenoid (Gougerot-Blum / golden lichen): component lichenoid and interface changes may be more noticeable. Spigariolo 2021
• Useful stains / IF / IHQ
  • Prussian Blue (Perls): confirms presence of hemosiderin. Huang 2018
  • IHC (if LCCT is suspected): CD3, CD4, CD8, CD20; assessment of epidermotropism/atypia and pattern. Smoller 1991, Sun 2023
  • Direct IF (if in doubt with vasculitis): to rule out immune deposits typical of immune complex vasculitis (interpretation always with clinical/histo). Spigariolo 2021
•  molecular tests
  • T cell receptor rearrangement (TCR-γ by PCR) when there is suspicion of mycosis fungoides/LCCTor persistent/atypical “PPD-like” lesions. Foo 2007, Sun 2023

• Leukocytoclastic vasculitis: neutrophils, leukocytoclasia, fibrinoid necrosis, marked extravasation. Huang 2018

• Early mycosis fungoides / PPD-like MF: epidermotropism of atypical lymphocytes, TCR clonality in appropriate context. Sun 2023, Foo 2007

• Granulomatous variant of DPP: Interstitial granulomas; may mimic granuloma annulare or sarcoidosis; clinical correlation is mandatory. Kerns 2009

• If the typical picture is asymptomatic: often it does not require extensive studies. Spigariolo 2021
• If there is extensive/atypical purpura, mucosal involvement, bleeding, systemic symptoms, or diagnostic uncertainty:
  • Complete blood count (Hb/platelets), PT/INR, aPTT
  • Liver/kidney profile
  • EGO (hematuria/proteinuria if vasculitis is suspected)
  • ± ESR/CRP depending on context
    (Example of a normal evaluation in pediatrics with Schamberg). Torrelo 2003
• Biopsy
  • Recommended type
    • Punch 4 mm (or 5 mm) including reticular dermisConsider a second biopsy if there is morphological variation or suspicion of CTCL. Çaytemel 2021
  • Technical considerations
    • Take from active purpuric lesion (more reddish/purple) and not only from residual hyperpigmentation (greater yield for extravasation/inflammation). Huang 2018
    • If the differential includes vasculitis: consider sample for IF direct (ideally in an appropriate medium) in addition to formalin. Spigariolo 2021
  •  Contraindications
    • Common relative complications (local infection, uncorrected coagulation disorder).
  • Fixing/labeling
    • 10% Formalin For H&E/IHQ; if direct IF is required, send separate sample in physiological saline (coordinate with the laboratory for collection). Spigariolo 2021

Central idea: benign condition; goal = control outbreaks/itching, minimize residual pigmentation, correct local factors, and monitor for “red flags”. Spigariolo 2021, Kimak 2024

• First line (practice)
  • Education and monitoring/supervised observation (especially in children; high resolution rate and no clear advantage over treatment in a cohort). Ollech 2020
  • Local measures: Avoid prolonged standing if it worsens; elevate legs; consider compression if there is stasis/varicoseveins. Spigariolo 2021
  • If itching/inflammation: Topical corticosteroid for short courses (variable evidence; useful symptomatically). Kimak 2024
  • Antioxidants (rutoside + ascorbic acid): A multicenter series suggests a high response in Schamberg/PPPD, with a better response if the duration is short (2×50 mg rutoside + 1000 mg vitamin C/day). Schober 2014
• Second/third line (depending on severity and refractoriness)
  • Pentoxifylline: reports and comparative trial; possible effect by modulation of lymphocyte/endothelial adhesion. Kano 1997, Panda 2004
  • Phototherapy: NB-UVB with responses in small series; consider in extensive/refractory cases. Fathy 2011, Dehghani 2025
  • Light/laser (e.g., PDL, excimer, PUVA, IPL): Evidence mainly from case series; may help in vascular/pigment components. Dehghani 2025
  • In rare variants or unusual histology, individualize (e.g., granulomatous). Kerns 2009
• General care and safety (clinical pharmacology)
  • Rutin/vitamin C: generally well tolerated; monitor GI and adherence; assess risk of lithiasis in predisposed individuals (high vitamin C) on an individual basis. Schober 2014
  • Pentoxifylline: Caution is advised due to the risk of bleeding, hypotension, interactions (anticoagulants/antiplatelet agents), and in renal/hepatic insufficiency according to local guidelines; monitor tolerance. Kano 1997
  • Phototherapy: phototoxicity, photoaging; PUVA with cumulative risks; document cumulative dose. Dehghani 2025
• Contraindications (for guidance only)
  • Phototherapy: classic contraindications (photodermatosis, relevant photosensitizing drugs, specific history).
  • Pentoxifylline: hypersensitivity/xanthines; precautions for comorbidity and anticoagulation (depending on context). Kano 1997

• Palpable purplenecrosis, blisters, severe pain, fever, arthralgia, hematuria/proteinuria → consider systemic vasculitis or another cause. Huang 2018

• Very extensive, progressive, infiltrated, very pruritic or recurrent lesions, clinicopathological discrepancy → discard mycosis fungoides/LCCT (serial biopsies + IHC ± TCR). Çaytemel 2021, Sun 2023, Foo 2007

• "Cayenne pepper"+ ochre pigmentation on legs, not palpable and without systemic data = DPP until proven otherwise. Sardana 2004

• Histology of capillaritis (lymphocytes + extravasation + hemosiderin) and absence of true vasculitis It's the key. Huang 2018

• If it “looks like DPP” but doesn’t improve, changes in morphology, or there is epidermotropism/clonability → consider PPD-like MF. Sun 2023

• Spigariolo CB, Giacalone S, Nazzaro G. Pigmented Purpuric Dermatoses: A Complete Narrative Review. J Clin Med. 2021, 10 (11): 2283. DOI: 10.3390/jcm10112283. PMID: 34070260.
  Summary: Comprehensive narrative review: clinical classification (subtypes), pathophysiological basis (capillaritis), differential diagnosis (incl. CTCL) and therapeutic options with heterogeneous level of evidence.
  PubMed

• Kimak A, Żebrowska A. Therapeutic Approach in Pigmented Purpuric Dermatoses—A Scoping Review. Int J Mol Sci. 2024, 25 (5): 2644. DOI: 10.3390/ijms25052644. PMID: 38473891.
  Summary: Scope review focused on treatments (topical, systemic, phototherapy and procedures), highlighting the overall low quality of evidence and stepwise practical proposals.
  PubMed

• Sardana K, Sarkar R, Sehgal VN. Pigmented purpuric dermatoses: an overview. Int J Dermatol. 2004;43(7):482–488. DOI: 10.1111/j.1365-4632.2004.02213.x. PMID: 15230884.
  Summary: Classic and concise review: semiology, typical distribution in legs, chronic course and practical diagnostic/therapeutic points.
  PubMed

• Kim DH, Seo SH, Ahn HH, Kye YC, Choi JE. Characteristics and Clinical Manifestations of Pigmented Purpuric Dermatoses. Ann Dermatol. 2015;27(4):404–410. DOI: 10.5021/ad.2015.27.4.404. PMID: 26273156.
  Summary: Clinical series describing distribution, subtypes (predominantly Schamberg) and associated comorbidities/medications, with useful clinical correlations.
  PubMed

• Huang YK, Lin CK, Wu YH. The pathological spectrum and clinical correlation of pigmented purpuric dermatosis—A retrospective review of 107 cases. J Cutan Pathol. 2018;45(5):325–332. DOI: 10.1111/cup.13118. PMID: 29381224.
  Summary: Clinicopathological correlation in a large cohort; delimits histological spectrum and supports differential points compared to vasculitis.
  PubMed

• Çaytemel C, Baykut B, Ağırgöl Ş, et al. Pigmented purpuric dermatosis: Ten years of experience… and awareness of mycosis fungoides in differential diagnosis. J Cutan Pathol. 2021;48(5):611–616. DOI: 10.1111/cup.13949. PMID:33368594.
  Summary: Real-world practice series with histological pattern analysis; underlines the need to consider mycosis fungoides when the presentation “looks like PPD” but the histology suggests otherwise.
  PubMed

• Smoller BR, Kamel OW. Pigmented purpuric eruptions: immunopathologic studies supportive of a common immunophenotype. J Cutan Pathol. 1991;18(6):423–427. DOI: 10.1111/j.1600-0560.1991.tb01378.x. PMID: 1723080.
  Summary: Immunopathological study showing predominance of T cell infiltrate and supporting localized immunological mechanism as a common basis among subtypes.
  PubMed

• Reinhardt L, Wilkin JK, Tausend R. Vascular abnormalities in lichen aureus. J Am Acad Dermatol. 1983;8(3):417–420. DOI: 10.1016/S0190-9622(83)70048-4. PMID: 6833542.
  Summary: Report with emphasis on capillary fragility/Koebnerization and persistence of lichen aureus; useful for understanding the vascular/local component.
  PubMed

• Ollech A, Paller AS, Kruse L, et al. Pigmented purpuric dermatosis in children: a retrospective cohort… J Eur Acad Dermatol Venereol. 2020;34(10):2402–2408. DOI: 10.1111/jdv.16397. PMID: 32236987.
  Summary: Pediatric cohort: high resolution rate, limited recurrences, and no progression to vasculitis/coagulopathy/CTCL on follow-up; compares treatment vs observation.
  PubMed

• Torrelo A, Requena C, Mediero IG, Zambrano A. Schamberg's purpura in children: a review of 13 cases. J Am Acad Dermatol. 2003;48(1):31–33. DOI: 10.1067/mjd.2003.25. PMID: 12522367.
  Summary: Pediatric series with extensive (normal) analytical evaluation and benign course; reinforces conservative approach in typical children.
  PubMed

• Schober SM, Peitsch WK, Bonsmann G, et al. Early treatment with rutoside and ascorbic acid… J Dtsch Dermatol Ges. 2014;12(12):1112–1119. DOI: 10.1111/ddg.12520. PMID: 25482694.
  Summary: Multicenter series with antioxidant combination (rutoside + vitamin C) and high clearance/improvement rates; suggests greater efficacy with shorter duration disease.
  PubMed

• 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. DOI: 10.1111/j.1468-3083.2010.03806.x. PMID: 21492246.
  Summary: Small series with NB-UVB showing clearing in Schamberg/Majocchi cases; supports phototherapy as an option in refractory patients.
  PubMed

• Kano Y, Hirayama K, Orihara M, Shiohara T. Successful treatment of Schamberg's disease with pentoxifylline. J Am Acad Dermatol. 1997;36(5 Pt 2):827–830. DOI: 10.1016/S0190-9622(97)70032-X. PMID: 9146559.
  Summary: Cases with response to pentoxifylline and mechanistic proposal (adhesion molecules) that connects with the immuno-endothelial hypothesis.
  PubMed

• Panda S, Malakar S, Lahiri K. Oral pentoxifylline vs topical betamethasone in Schamberg disease… Arch Dermatol.2004;140(4):491–493. DOI: 10.1001/archderm.140.4.491. PMID: 15096387.
  Summary: Randomized comparative trial (short format) supporting pentoxifylline as a systemic alternative to topical corticosteroid in Schamberg.
  PubMed

• Dehghani A, Seddigh MA, Jafarzadeh A, et al. A systematic review of the safety and effectiveness of laser and light therapies… Lasers Med Sci. 2025, 40 (1): 401. DOI: 10.1007/s10103-025-04615-4. PMID: 41032121.
  Summary: Systematic review of phototherapy and laser (NB-UVB, PUVA, PDL, excimer, etc.) with promising results but evidence dominated by series/cases.
  PubMed

• Sun J, Liu K, Dang J, et al. Pigmented purpura dermatosis-like mycosis fungoides… Eur J Dermatol.2023;33(6):635–641. DOI: 10.1684/ejd.2023.4574. PMID: 38465544.
  Summary: Cases and review of MF that mimics PPD; provides clinicopathological keys to avoid overlooking CTCL in atypical or persistent “PPD”.
  PubMed

• Kerns MJJ, Mallatt BD, Shamma HN. Granulomatous pigmented purpura: an unusual histological variant. Am J Dermatopathol. 2009;31(1):77–80. DOI: 10.1097/DAD.0b013e31817e23c9. PMID: 19155731.
  Summary: Describes a granulomatous variant that broadens the histological spectrum and reinforces the need for clinical correlation and granulomatous differentials.
  PubMed

• Foo CCI, Tang MBY, Chong TKL, Sun YJ, Tan SH. T-cell receptor-gamma gene analysis… cutaneous T-cell lymphoma. Australas J Dermatol. 2007;48(3):156–160. DOI: 10.1111/j.1440-0960.2007.00370.x. PMID: 17680965.
  Summary: Evaluates TCR-γ PCR as a diagnostic adjunct in CTCL and mentions “pigmented purpura-like MF” type subgroups; useful for deciding when to request clonability.
  PubMed