Multiple myeloma is a cancer originating in plasma cells. While primarily affecting bone marrow and bones, this cancer can also manifest on the skin. Skin changes are diverse and can be subtle, making them challenging to recognize without medical insight. Understanding these skin manifestations is important for patients and caregivers.
Direct Skin Manifestations
Direct skin manifestations, known as myeloma cutis, occur when myeloma cells infiltrate the skin. These lesions typically present as firm, painless nodules or plaques, often reddish-brown to purplish.
These infiltrations can appear anywhere, often on the trunk or face. Myeloma cutis can resemble other common skin conditions, complicating diagnosis. Direct skin involvement is less common than other myeloma-related skin issues.
Indirect Skin Manifestations
Most skin changes linked to multiple myeloma are indirect consequences of the disease or its complications.
Amyloidosis
Amyloidosis, where abnormal protein deposits accumulate in tissues including the skin, is an indirect manifestation. This can lead to waxy papules or plaques, especially around the eyelids, neck, or in skin folds. Easy bruising, known as periorbital purpura or “raccoon eyes,” is another sign, from fragile blood vessels due to amyloid deposition.
Cryoglobulinemia
Cryoglobulinemia, where abnormal proteins react to cold, can cause various skin issues. These may include vasculitic lesions, purpura (small red or purple spots), livedo reticularis (a net-like pattern of discoloration), or skin ulcers. Manifestations are common on extremities, where skin temperatures are often cooler. Cold-induced cryoglobulin precipitation can lead to inflammation and small blood vessel damage.
Coagulation abnormalities
Coagulation abnormalities, stemming from platelet dysfunction or bleeding tendencies, can result in increased bruising. Petechiae (small, pinpoint red spots) and ecchymoses (larger purplish bruises) are common. These occur due to impaired blood clotting mechanisms.
Hypercalcemia
Elevated blood calcium (hypercalcemia) can contribute to skin symptoms. Pruritus, or generalized itching, is common. Rarely, hypercalcemia can also lead to calcinosis cutis, where calcium salts deposit in the skin, forming firm, whitish nodules.
Paraneoplastic syndromes
Multiple myeloma can trigger paraneoplastic syndromes, rare immune responses causing diverse skin conditions not directly from cancer cells. Examples include Sweet’s syndrome (tender, red plaques and nodules, often with fever) and pyoderma gangrenosum (rapidly enlarging, painful ulcers with undermined borders). These dermatoses vary widely, reflecting complex immune interactions.
Treatment-Related Skin Reactions
Skin manifestations can arise as side effects of multiple myeloma treatments. These differ from direct or indirect disease effects.
Common reactions include generalized rashes like maculopapular eruptions (flat, red areas with small bumps). Erythema (widespread redness) and pruritus (itching) can also occur.
Some treatments can cause hand-foot syndrome, involving redness, swelling, pain, and sometimes blistering on palms and soles. Photosensitivity (increased sun sensitivity) can cause exaggerated sunburn reactions. Brittle nails or changes in nail color and texture may occur.
Hair thinning or loss is another potential side effect. Injectable medications often cause local reactions like redness, swelling, and pain at the injection site. While frequent, these reactions are often manageable with medical guidance.
Importance of Medical Consultation
Prompt medical evaluation for any new or concerning skin changes is important for individuals with multiple myeloma or suggestive symptoms.
Accurate diagnosis requires medical expertise, as many skin conditions mimic others, making self-diagnosis unreliable. Healthcare professionals can differentiate between direct infiltration, indirect effects, and treatment-related side effects.
Skin changes can be an important diagnostic clue, sometimes indicating underlying multiple myeloma. They can also indicate disease progression or provide insights into treatment effectiveness or side effects. Consulting a healthcare team for accurate assessment and management of any observed skin changes is recommended.