Myelodysplastic syndrome (MDS) produces skin changes in a meaningful minority of patients, and those changes range from painful red nodules and ulcers to blistering eruptions and purplish spots caused by inflamed blood vessels. A systematic review of 134 reported cases found six broad categories of skin involvement, with neutrophilic dermatoses being the most common by a wide margin. Perhaps more striking than the variety of rashes is their timing: roughly a third of patients developed skin problems before MDS was even diagnosed, which means a dermatologist’s office visit can sometimes be the first clue that something is wrong in the bone marrow.
How Common Are Skin Problems in MDS
Estimates vary depending on how hard you look. A prospective study of 157 MDS patients at a single center found that about one in ten had skin lesions considered associated with their disease, with neutrophilic dermatosis being the most frequent type, followed by specific neoplastic skin infiltrates and vasculitis.1PubMed. Prevalence and prognostic value of cutaneous manifestations in patients with myelodysplastic syndrome That number likely underestimates the true scope, because many subtle or transient rashes go unreported, and the autoimmune and inflammatory complications of MDS are still being catalogued. The systematic review that pooled data from 88 published reports identified 134 patients across six categories of skin involvement: neutrophilic dermatoses (64 cases), vasculitis (21), granulomatous disease (8), connective tissue disease (7), panniculitis (4), and immunobullous disease (1), plus 29 cases that did not fit neatly into any single bucket.2PubMed Central. Cutaneous manifestations of myelodysplastic syndrome: A systematic review
When Skin Changes Appear Relative to Diagnosis
One of the most clinically useful findings is that skin manifestations do not wait for a formal MDS diagnosis. In the same systematic review, about a quarter of skin problems showed up at the same time MDS was identified, roughly 40 percent appeared afterward (anywhere from one month to eleven years later), and about 35 percent actually preceded the MDS diagnosis, sometimes by as long as eighteen years.2PubMed Central. Cutaneous manifestations of myelodysplastic syndrome: A systematic review That last group is the one that matters most for early detection. If you develop an unexplained neutrophilic dermatosis or recurrent vasculitis, and routine blood work shows unexplained low counts or abnormal-looking cells, pushing for a bone marrow biopsy can sometimes catch MDS years before it would have been found otherwise.
Sweet Syndrome and Other Neutrophilic Dermatoses
Neutrophilic dermatoses are the skin conditions most tightly linked to MDS. The group includes Sweet syndrome (also called acute febrile neutrophilic dermatosis), pyoderma gangrenosum, and a few rarer variants. All share a defining feature under the microscope: a dense accumulation of neutrophils in the skin without any sign of infection driving them there.
Sweet syndrome is the most recognized of these. It typically presents as tender, reddish-purple papules or plaques, often on the face, neck, and upper limbs, accompanied by fever and elevated inflammatory markers. About a fifth of all Sweet syndrome patients have an associated malignancy, and up to 80 percent of malignancy-associated Sweet syndrome cases involve a blood cancer, predominantly MDS or acute myeloid leukemia (AML).3PubMed Central. Sweet Syndrome Associated with Myelodysplastic Syndrome—A Review of a Multidisciplinary Approach In a cohort study of 93 Sweet syndrome patients, those whose Sweet syndrome was linked to MDS tended to follow a chronic, relapsing course, unlike those with AML, who typically had a single flare that resolved quickly with treatment.4PubMed Central. Sweet Syndrome: Clinical Presentation, Malignancy Association, Autoinflammatory Disorders and Treatment Response in a Cohort of 93 Patients with Long-term Follow-up That relapsing pattern is a clinical red flag: Sweet syndrome that keeps coming back should prompt evaluation for an underlying myeloid disorder.
Pyoderma gangrenosum is the more destructive cousin. It begins as a pustule or blister that rapidly breaks down into a deep, painful ulcer with violaceous undermined edges. The ulcers can be large and disfiguring, and they heal slowly because the underlying neutrophilic inflammation keeps fueling tissue destruction. Standard wound care alone does not work; the immune-mediated process driving the ulcer has to be addressed.5PubMed Central. Severe pyoderma gangrenosum caused by myelodysplastic syndrome successfully treated with decitabine administered by a noncytotoxic regimen One important caution for anyone managing wounds in an MDS patient: pyoderma gangrenosum exhibits pathergy, meaning it can worsen after surgical debridement or biopsy at the wound edge. Any new ulcer that gets worse after a procedure rather than better should raise suspicion.
The Inflammatory Machinery Behind MDS Skin Disease
Research into why MDS produces skin inflammation has pointed to a shared immune signature. A study using gene expression profiling of skin biopsies found that MDS-associated skin lesions and the skin lesions of VEXAS syndrome (a recently identified autoinflammatory condition also rooted in bone marrow dysfunction) share closely related molecular profiles. Both conditions show strong activation of interferon pathways, tumor necrosis factor signaling, and interleukin-1β pathways, along with upregulation of apoptosis-related genes.6JAMA Dermatology. Inflammatory Signatures in VEXAS Syndrome, Myelodysplasia Cutis, and Sweet Syndrome In plain terms, the abnormal bone marrow in MDS churns out immune cells that are primed for inflammation. When those cells reach the skin, they create an inflammatory environment that can manifest as any of the conditions described above, depending on which specific pathways dominate in a given patient.
Vasculitis in MDS
Vasculitis, or inflammation of blood vessels, is the second most common skin manifestation. In the skin it usually appears as palpable purpura: raised, non-blanching reddish-purple spots, most often on the lower legs. A report describing 21 MDS patients with associated vasculitis found that skin lesions were present in 81 percent of them, but the disease was rarely limited to the skin alone. Joint pain occurred in over 60 percent, kidney involvement in over 40 percent, and fever in nearly half.7Blood. Association between Vasculitides and Myelodysplastic Syndrome (MDS): A Report on 21 Cases That systemic overlap is worth emphasizing: when vasculitis occurs alongside MDS, the rash on the legs may be just the visible tip of a broader inflammatory process hitting the kidneys, joints, and peripheral nerves.
Cutaneous leukocytoclastic vasculitis (CLV), the most common histological pattern seen in these cases, involves inflammation and destruction of small blood vessels in the upper dermis. Fewer than one percent of all CLV cases are associated with malignancy, which means the vast majority of people who develop this type of rash do not have cancer.8The American Journal of the Medical Sciences. Cutaneous Leukocytoclastic Vasculitis Associated with Myelodysplastic Syndrome But when CLV appears in an older patient with unexplained cytopenias or an already-known myeloid disorder, it should not be dismissed as an isolated skin problem.
Leukemia Cutis and What It Signals
Not all MDS-related skin findings are inflammatory. Leukemia cutis refers to actual infiltration of the skin by malignant myeloid blast cells, and it carries a different and more urgent message. In an MDS patient, the appearance of leukemia cutis is considered a sign that the disease is transforming, or is about to transform, into acute leukemia.9PubMed. Myeloid leukemia cutis in the setting of myelodysplastic syndrome: a crucial dermatological diagnosis Clinically, leukemia cutis can look like firm, reddish-brown or violaceous papules, nodules, or plaques. It sometimes resembles Sweet syndrome or other neutrophilic dermatoses on the surface, but biopsy reveals sheets of immature blast cells rather than mature neutrophils. A case report describing leukemia cutis alongside a myeloid sarcoma (a tumor mass composed of blasts outside the bone marrow) confirmed the diagnosis through skin biopsy showing massive infiltration by myeloblastic cells.10PubMed Central. Successful 5-azacytidine treatment of myeloid sarcoma and leukemia cutis associated with myelodysplastic syndrome: A case report and literature review
The practical takeaway is that any new skin nodule in an MDS patient deserves a biopsy rather than empiric treatment, because the distinction between an inflammatory neutrophilic dermatosis and leukemia cutis fundamentally changes both prognosis and management.
VEXAS Syndrome and Its Overlap with MDS
VEXAS syndrome, first described in 2020, is caused by somatic mutations in the UBA1 gene and produces a striking combination of systemic inflammation, blood count abnormalities, and skin disease. In a study of 112 VEXAS patients, skin involvement was present in 83 percent, and it was the presenting feature in over 60 percent. MDS was present in about 15 percent of the cohort.11JAMA Dermatology. Skin Manifestations of VEXAS Syndrome and Associated Genotypes The overlap matters because VEXAS can look almost identical to MDS-associated neutrophilic dermatosis on biopsy. Research has shown that in VEXAS patients with neutrophilic dermatosis, the inflammatory cells infiltrating the skin are actually derived from the UBA1-mutated myeloid clone, meaning the abnormal bone marrow cells are directly seeding the skin lesion.12PubMed Central. Distinction between clonal and paraclonal cutaneous involvements in VEXAS syndrome
For patients and clinicians, this means that a middle-aged or older man presenting with recurrent Sweet syndrome, unexplained fevers, and low blood counts should be evaluated not only for MDS but also for VEXAS, because treatment strategies differ.
Less Common Skin Manifestations
Beyond the major categories, MDS has been associated with a scattering of less frequent skin conditions. Panniculitis, inflammation of the subcutaneous fat layer, can produce tender red nodules under the skin, sometimes resembling erythema nodosum. A reported case described a patient who developed erythema nodosum along with serositis (inflammation of the membrane lining the chest and abdomen) as manifestations of MDS.13PubMed Central. A case of erythema nodosum and serositis associated with myelodysplastic syndrome
Immunobullous diseases, conditions in which the immune system attacks the skin’s structural proteins and causes blistering, are rare but documented. One report described an elderly man with MDS who developed bullous pemphigoid, a blistering condition, alongside neoplastic cell infiltration of the skin. His biopsy showed both the subepidermal blisters characteristic of bullous pemphigoid and a dermal infiltrate of blast cells.14PubMed. Bullous pemphigoid in association with cutaneous lesions specific to a myelodysplastic syndrome Cases like this illustrate how MDS can produce multiple overlapping skin pathologies in the same patient, making diagnosis challenging.
Drug-Related Skin Reactions in MDS Treatment
Some of the skin problems MDS patients experience come not from the disease itself but from its treatment. Two of the most widely used drugs in MDS management, lenalidomide and azacitidine, both carry significant skin side effects.
Lenalidomide, used primarily in lower-risk MDS with a specific chromosomal deletion, causes rash in up to a third of patients in clinical trials. While severe rash is uncommon, analysis of post-marketing safety data showed that nonserious rash was the leading cause of permanent early discontinuation of the drug in the MDS population, with most of those discontinuations happening within the first two treatment cycles.15PubMed. Practical Management of Lenalidomide-Related Rash This is worth knowing because many of those rashes are manageable with dose adjustments or supportive care, and stopping the drug prematurely can deprive patients of a treatment that is working for their blood counts.16Journal of the Advanced Practitioner in Oncology. Practical Guide to Management of Lenalidomide-Related Rash in Patients With MDS
Azacitidine, given by subcutaneous injection, produces its own set of skin reactions. A review of cases identified three subtypes: systemic cutaneous reactions (widespread rashes), neutrophilic dermatosis triggered by the drug, and injection-site erythema with a flare-up pattern.17PubMed. Cutaneous adverse events induced by azacitidine in myelodysplastic syndrome patients: Case reports and a lesson from published work review The injection-site reactions can look alarming, with spreading redness and swelling, but they are generally self-limited. The key challenge is distinguishing a drug reaction from a new MDS-related skin manifestation, since both can present as neutrophilic inflammation. Biopsy and clinical context usually sort this out.
What Skin Type Tells You About Prognosis
The type of skin manifestation a patient develops appears to carry prognostic information, though the data come mainly from case reports and small series rather than large trials. In the systematic review of 134 patients, overall mortality was about 40 percent, and roughly a third progressed to AML. Granulomatous skin disease carried the highest fatality rate at over 60 percent, followed by vasculitis at 50 percent. Neutrophilic dermatoses had a fatality rate of about 39 percent, while connective tissue disease had the lowest at roughly 14 percent.18Skin Health and Disease. Cutaneous Manifestations of Myelodysplastic Syndrome: A Systematic Review Among patients who progressed to AML, half had neutrophilic dermatoses, though this association did not reach statistical significance in the available data.
Leukemia cutis, as discussed earlier, stands apart as a particularly ominous finding because it signals that blast cells have already escaped the marrow and are establishing themselves in other tissues.9PubMed. Myeloid leukemia cutis in the setting of myelodysplastic syndrome: a crucial dermatological diagnosis Any new skin lesion in an MDS patient should prompt re-evaluation of the disease status, not just dermatologic management of the rash.
How Skin Manifestations Are Treated
Treatment depends on whether the skin problem is inflammatory, neoplastic, or drug-related. For inflammatory conditions like Sweet syndrome and pyoderma gangrenosum, corticosteroids are the first-line approach. A study examining autoimmune and paraneoplastic phenomena in MDS found that immunosuppressive therapy, primarily prednisone, controlled the autoimmune manifestations in the vast majority of treated patients and in some cases even produced improvement in the underlying blood counts.19PubMed. Paraneoplastic autoimmune phenomena in patients with myelodysplastic syndromes: response to immunosuppressive therapy A case report described a patient with pyoderma gangrenosum whose skin lesion responded dramatically to pulse methylprednisolone followed by maintenance prednisone, though the MDS later transformed to leukemia despite the skin improvement.20PubMed. Successful treatment of pyoderma gangrenosum that developed in a patient with myelodysplastic syndrome
When the skin disease proves refractory to steroids, or when it keeps relapsing every time steroids are tapered, treating the underlying MDS directly can be effective. A case of refractory Sweet syndrome achieved complete remission when the patient was started on azacitidine for MDS, simultaneously clearing both the skin disease and the abnormal blood counts.21PubMed. Complete remission of Sweet’s syndrome after azacytidine treatment for concomitant myelodysplastic syndrome Similarly, decitabine, another hypomethylating agent, has been used to treat pyoderma gangrenosum driven by an underlying myeloid malignancy.5PubMed Central. Severe pyoderma gangrenosum caused by myelodysplastic syndrome successfully treated with decitabine administered by a noncytotoxic regimen The logic is straightforward: if the abnormal bone marrow clone is driving the skin inflammation, suppressing that clone should reduce the skin disease.
Infections That Mimic MDS Skin Disease
MDS patients are immunocompromised because their bone marrow produces dysfunctional immune cells and often too few of them. This makes them susceptible to unusual infections that can present as skin lesions and create diagnostic confusion. A reported case described an 80-year-old MDS patient who developed exfoliating skin lesions and eruptions on his face and scalp that turned out to be caused by Mycobacterium colombiense, an uncommon nontuberculous mycobacterium. The infection resolved with a combination of antibiotics.22J-STAGE / Internal Medicine. Disseminated Cutaneous Infection of Mycobacterium colombiense in a Patient with Myelodysplastic Syndrome
Fungal infections, atypical bacterial infections, and viral reactivations can all produce skin findings in MDS patients that overlap visually with the inflammatory conditions described throughout this article. This is why biopsy, culture, and sometimes molecular testing are so important. Treating what looks like Sweet syndrome with steroids when it is actually an infection will make things worse.
Skin After Stem Cell Transplant
For patients with higher-risk MDS who undergo allogeneic stem cell transplant (the only potentially curative treatment), the skin can become a battleground in a different way. Graft-versus-host disease, in which donor immune cells attack the recipient’s tissues, affects the skin earlier and more frequently than any other organ. Acute cutaneous GVHD typically appears as a maculopapular rash that can range from a mild eruption limited to the palms and soles to a severe, diffuse process resembling a burn. Chronic cutaneous GVHD can produce thickened, tight skin resembling scleroderma, patchy discoloration, and mucosal involvement.23PubMed Central. Cutaneous graft-versus-host disease after hematopoietic stem cell transplant – a review
For MDS patients who have been living with disease-related skin problems before transplant, this adds another layer of complexity. A rash that develops post-transplant could be GVHD, recurrence of a prior MDS-associated condition, infection in the setting of immunosuppression, or a drug reaction. Sorting this out often requires biopsy, and sometimes even biopsy is ambiguous. The clinical context, including the timing relative to transplant and the drugs the patient is currently taking, usually guides the final interpretation.