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PubMed This is a summary of 23 peer-reviewed journal articles Updated
Rheumatology

Building Your Foundation: Understanding MRH

At a Glance

Multicentric reticulohistiocytosis (MRH) is a rare immune-cell disorder that causes skin nodules and potentially destructive arthritis. Prompt rheumatology care, joint monitoring, individualized cancer screening, and systemic treatment help protect joint function.

Receiving a diagnosis of Multicentric Reticulohistiocytosis (MRH) can feel like being dropped into an unfamiliar world with no map. Because only about 300 cases have been reported in the medical literature worldwide, you may find that even experienced doctors have never encountered it in person [1][2]. This rarity can bring a profound sense of isolation, but it is important to remember that you are part of a small, documented community. Your medical team has access to the collective knowledge of those case reports to guide your care.

The Biology of MRH

MRH is classified as a rare non-Langerhans cell histiocytosis, a group of disorders where the body’s own immune cells—specifically histiocytes and macrophages—behave abnormally [3][4]. In a healthy body, these cells act as “scavengers” that protect you from infection. In MRH, these cells gather in clusters within your skin, joints, and occasionally internal organs [5].

When viewed under a microscope, these clusters contain large, unique cells with a “ground-glass” appearance [6]. While we do not yet fully understand why this happens, research suggests that these cells release inflammatory signals and trigger osteoclasts—the cells that break down bone—which is why the disease can be so aggressive toward your joints [7][8].

A Dual-Front Disease

MRH primarily presents itself in two ways, often appearing around the same time:

  • Skin Nodules: You may notice firm, reddish-brown bumps (papules) or nodules. These frequently appear on the hands, face, and ears [6]. A classic sign of MRH is the “coral bead” appearance—a row of tiny bumps along the edges of your fingernails [9].
  • Destructive Arthritis: Unlike many common forms of arthritis, the joint involvement in MRH can be rapidly progressive. It often affects the small joints at the very ends of the fingers (DIP joints), but it can involve large joints like the hips or shoulders as well [10][7].

The Need for Urgent Care

While MRH is not typically an immediate threat to your life that requires a trip to the emergency room, it does require urgent rheumatology assessment [11][12]. The disease has the potential to cause arthritis mutilans, a severe, destructive form of arthritis where bone is reabsorbed, leading to permanent joint collapse and loss of function [1].

Erosions—small pits or holes in the bone—can appear rapidly [13]. Because this structural damage generally cannot be reversed once it occurs, starting systemic (body-wide) treatment promptly is the most critical step you can take to protect your mobility and independence [7][14].

Screening for Associated Conditions

A key part of your initial workup will involve an individualized evaluation. MRH is reported to be associated with other health issues:

  1. Malignancy (Cancer): Approximately 25% to 30% of reported MRH cases have an associated malignancy [15][16]. While this means most patients do not have cancer, your doctor will perform age- and risk-appropriate cancer screenings based on your symptoms [17]. It is important to pursue this screening as directed by your clinician, even if your MRH symptoms improve [18].
  2. Autoimmune Disorders: Some reported cases (around 29% to 33% in small series) involve an overlapping autoimmune disease, such as Sjögren syndrome or rheumatoid arthritis [15][3]. Your doctor may order specific blood tests if your physical exam or symptoms suggest this possibility.
  3. Internal Organs: Occasionally, MRH can affect the lungs, heart, or other organs [5]. Routine whole-body imaging is not standard for everyone, but testing may be ordered if you develop specific symptoms [19].

Navigating Your Care

Because there is no single FDA-approved treatment for MRH, your doctors will likely use off-label medications based on case reports to calm your immune system. Common first-line treatments include corticosteroids (like prednisone) and methotrexate [20][10]. If these are not enough, your team may explore biologic therapies or JAK inhibitors, which have shown promise in managing symptoms in some cases [21][22].

Your care will require a partnership, usually between a rheumatologist (joint specialist) and a dermatologist (skin specialist) [23]. By acting quickly and maintaining a tailored screening plan, you and your team can work to manage the disease and preserve your joint health.

Common questions in this guide

What is multicentric reticulohistiocytosis (MRH)?
MRH is a rare non-Langerhans cell histiocytosis, meaning abnormal immune cells build up in the skin, joints, and sometimes internal organs. It can produce firm skin nodules and rapidly progressive, destructive arthritis.
What skin and joint symptoms can MRH cause?
MRH can cause firm reddish-brown papules or nodules on the hands, face, ears, and around the fingernails, sometimes creating a coral-bead pattern. It may also cause pain, stiffness, and rapidly progressive arthritis in small or large joints.
Why does MRH require prompt treatment?
MRH can cause bone erosions and, in severe cases, arthritis mutilans, a destructive form of arthritis in which bone is reabsorbed and joints can collapse. Damage may become permanent, so prompt rheumatology assessment and systemic treatment are important.
Does MRH mean I have cancer?
No. Cancer has been reported alongside MRH in about 25% to 30% of reported cases, which means most people with MRH do not have cancer. Your clinician should recommend screening based on your age, medical history, symptoms, and risk factors, even if MRH symptoms improve.
What medicines are used to treat MRH?
There is no single FDA-approved treatment specifically for MRH, so doctors often use medicines off label based on clinical experience and case reports. Common options include corticosteroids such as prednisone and methotrexate; biologic therapies or JAK inhibitors may be considered when initial treatment is not enough.
Which specialists usually care for people with MRH?
A rheumatologist typically evaluates the arthritis and coordinates systemic treatment, while a dermatologist assesses the skin findings. Because MRH is rare, your doctors may also seek advice from an academic center with experience in rare histiocytoses.
Could MRH be linked to autoimmune disease or organ problems?
Some people with MRH also have autoimmune diseases such as Sjögren syndrome or rheumatoid arthritis. MRH can occasionally involve organs such as the lungs or heart, so testing is usually guided by symptoms and examination rather than routine whole-body imaging for everyone.

Questions For You

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Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my imaging and symptoms, what is the current state of my joints, and are there signs of erosions or early damage?
  2. 2.What is my specific plan for cancer screening based on my age and medical history?
  3. 3.How will we monitor my response to treatment to ensure we are acting quickly enough to prevent permanent joint destruction?
  4. 4.Should we test for autoimmune conditions based on my current symptoms and physical exam?
  5. 5.Are there specific symptoms of internal organ involvement that I should report to you immediately?
  6. 6.Do you have experience treating MRH, or can you consult with a specialist at a major academic center who has experience with rare histiocytoses?

References

References (23)
  1. 1

    Multicentric Reticulohistiocytosis: Elective Excision of Symptomatic Hand Nodules With 1-Year Follow-Up.

    Mead M, Baes T, Dass G

    The Journal of hand surgery 2020; (45(5)):457.e1-457.e5 doi:10.1016/j.jhsa.2019.06.001.

    PMID: 31320232
  2. 2

    Multicentric reticulohistiocytosis with prominent skin lesions and arthritis: A case report.

    Xu XL, Liang XH, Liu J, et al.

    World journal of clinical cases 2022; (10(22)):7913-7923 doi:10.12998/wjcc.v10.i22.7913.

    PMID: 36158473
  3. 3

    Multicentric Reticulohistiocytosis Associated with an Early Form of Systemic Lupus Erythematosus: A Case Report of a Rare Disease, with Mini Review of the Literature.

    Mariotti EB, Corrà A, Lemmi E, et al.

    Journal of clinical medicine 2022; (11(21)) doi:10.3390/jcm11216529.

    PMID: 36362761
  4. 4

    Multicentric reticulohistiocytosis: a critical review.

    Selmi C, Greenspan A, Huntley A, Gershwin ME

    Current rheumatology reports 2015; (17(6)):511 doi:10.1007/s11926-015-0511-6.

    PMID: 25900189
  5. 5

    Multicentric Reticulohistiocytosis Presenting As Acute Pericarditis With Moderate-Sized Pericardial Effusion: A Case Report and Review of Multicentric Reticulohistiocytosis Treatment.

    Mandyam S, Onteddu J, Ray R, et al.

    Cureus 2023; (15(6)):e39953 doi:10.7759/cureus.39953.

    PMID: 37416020
  6. 6

    Reddish-brown, papulonodular skin lesions in the periungual region.

    Nosewicz J, Moad JC, Kaffenberger J

    Dermatology online journal 2023; (29(1)) doi:10.5070/D329160219.

    PMID: 37040916
  7. 7

    The utility of FDG-PET/CT imaging in the evaluation of multicentric reticulohistiocytosis: A case report.

    Asano T, Suzutani K, Watanabe A, et al.

    Medicine 2018; (97(33)):e11449 doi:10.1097/MD.0000000000011449.

    PMID: 30113451
  8. 8

    Assessment and effective targeting of Interleukin-1 in multicentric reticulohistyocytosis.

    Aouba A, Leclerc-Mercier S, Fraitag S, et al.

    Joint bone spine 2015; (82(4)):280-3.

    PMID: 25776445
  9. 9

    Multicentric Reticulohistiocytosis.

    Goldberg LA, Hsu S

    Skinmed 2024; (22(6)):452-453.

    PMID: 39748578
  10. 10

    Clinical characteristics of multicentric reticulohistiocytosis and distinguished features from rheumatoid arthritis: a single-center experience in China.

    Zou XJ, Qiao L, Li F, et al.

    Orphanet journal of rare diseases 2022; (17(1)):164 doi:10.1186/s13023-022-02311-y.

    PMID: 35413870
  11. 11

    Efficacy of Vinblastine and Prednisone in Multicentric Reticulohistiocytosis With Onset in Infancy.

    Jha VK, Kumar R, Kunwar A, et al.

    Pediatrics 2016; (137(6)).

    PMID: 27199388
  12. 12

    A refractory polyarthritis revealing a multicentric reticulohistiocytosis.

    Deville-Cavellin O, Nallet A, Ralandison S, et al.

    Modern rheumatology case reports 2026; (10(1)) doi:10.1093/mrcr/rxag021.

    PMID: 41786636
  13. 13

    Multicentric Reticulohistiocytosis Exhibiting Positive HLA-B*07 and HLA-B*08: A Case Report.

    Rezuș E, Burlui MA, Cardoneanu A, et al.

    Medicina (Kaunas, Lithuania) 2020; (56(9)) doi:10.3390/medicina56090456.

    PMID: 32911791
  14. 14

    A case report of multicentric reticulohistiocytosis with atypical cutaneous presentation.

    Chen X, An L, Jiang Z, Jia Y

    Frontiers in immunology 2024; (15()):1344313 doi:10.3389/fimmu.2024.1344313.

    PMID: 38426104
  15. 15

    Multicentric reticulohistiocytosis: the Mayo Clinic experience (1980-2017).

    Sanchez-Alvarez C, Sandhu AS, Crowson CS, et al.

    Rheumatology (Oxford, England) 2020; (59(8)):1898-1905 doi:10.1093/rheumatology/kez555.

    PMID: 31742640
  16. 16

    Multicentric reticulohistiocytosis revealing a ductal breast cancer in situ: A case report with dermoscopic and histopathological findings.

    Palma Peña S, Neely Erdos G, Buchroithner Haase C, Pinto Viguera C

    Medwave 2024; (24(5)):e2914 doi:10.5867/medwave.2024.05.2914.

    PMID: 38896878
  17. 17

    Multicentric reticulohistiocytosis masquerading as cutaneous connective tissue disease.

    Fronek L, Bindernagel R, Segars K, Miller R

    Dermatology online journal 2021; (27(3)).

    PMID: 33865276
  18. 18

    A Novel Case of Multicentric Reticulohistiocytosis Associated with Renal Cell Carcinoma Successfully Treated with Infliximab and Methotrexate.

    Patel S, Alhajj M, Brimhall C

    Case reports in dermatology 2023; (15(1)):10-16 doi:10.1159/000528254.

    PMID: 36632441
  19. 19

    Malignancy-associated Multicentric Reticulohistocytosis Mimicking Dermatomyositis-like Features, with a Significant Ultrasound Finding.

    Inomata H, Asatani S, Ikumi N, et al.

    Internal medicine (Tokyo, Japan) 2026; (65(12)):1710-1715 doi:10.2169/internalmedicine.6032-25.

    PMID: 41192909
  20. 20

    Looks Can Be Deceiving: A Case Report on Multicentric Reticulohistiocytosis Successfully Treated with Rituximab.

    Lim K, D'Souza J, Vasquez JB, Vuyyuru S

    Cureus 2017; (9(5)):e1220 doi:10.7759/cureus.1220.

    PMID: 28589069
  21. 21

    Successful treatment of multicentric reticulohistiocytosis with JAK inhibitor: a case series.

    Hilliquin S, Dupin N, Franck N, et al.

    RMD open 2026; (12(2)) doi:10.1136/rmdopen-2025-006661.

    PMID: 42097694
  22. 22

    Upadacitinib-Induced Remission in Multicentric Reticulohistiocytosis: Expanding the Therapeutic Role of JAK Inhibition.

    Pamfil C, Taki MA, Candrea E, et al.

    International journal of molecular sciences 2026; (27(6)) doi:10.3390/ijms27062898.

    PMID: 41898754
  23. 23

    Skin Manifestation Associated With Multicentric Reticulohistiocytosis.

    Yamamoto T

    Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases 2022; (28(1)):e234-e239 doi:10.1097/RHU.0000000000001679.

    PMID: 33337805

This MRH overview is for informational purposes only and does not constitute medical advice. Your rheumatologist and dermatologist can interpret your symptoms, imaging, screening needs, and treatment options.