It may give rise to paraplegia in late-presenting cases.When the disease is well-controlled, neurological symptoms may result from current treatments, some of which may cause peripheral neuropathy, manifesting itself as numbness or pain in the hands, feet, and lower legs. Mouth
The initial symptoms may involve pain, numbness, swelling, expansion of the jaw, tooth mobility, and radiolucency. Multiple myeloma in the mouth can mimic common teeth problems like periapical abscess or periodontal abscess, gingivitis, periodontitis, or other gingival enlargement or masses. Cause
The cause of multiple myeloma is generally unknown. Risk factors
Monoclonal gammopathy of undetermined significance (MGUS) increases the risk of developing multiple myeloma. MGUS transforms to multiple myeloma at the rate of 1% to 2% per year, and almost all cases of multiple myeloma are preceded by MGUS. Smoldering multiple myeloma increases the risk of developing multiple myeloma. Individuals diagnosed with this premalignant disorder develop multiple myeloma at a rate of 10% per year for the first 5 years, 3% per year for the next 5 years, and then 1% per year. Obesity is related to multiple myeloma with each increase of body mass index by five increasing the risk by 11%.Studies have reported a familial predisposition to myeloma. Hyperphosphorylation of a number of proteins—the paratarg proteins—a tendency that is inherited in an autosomal dominant manner, appears a common mechanism in these families. This tendency is more common in African-American with myeloma and may contribute to the higher rates of myeloma in this group.
Contact
Contact dermatitis is of two types: allergic (resulting from a delayed reaction to an allergen, such as poison ivy, nickel, or Balsam of Peru), and irritant (resulting from direct reaction to a detergent, such as sodium lauryl sulfate, for example). Some substances act both as allergen and irritants (wet cement, for example). Other substances cause a problem after sunlight exposure, bringing on phototoxic dermatitis. About three-quarters of cases of contact eczema are of the irritant type, which is the most common occupational skin disease. Contact eczema is curable, provided the offending substance can be avoided and its traces removed from ones environment. (ICD-10 L23; L24; L56.1; L56.0)

Seborrhoeic
Seborrhoeic dermatitis or seborrheic dermatitis is a condition sometimes classified as a form of eczema that is closely related to dandruff. It causes dry or greasy peeling of the scalp, eyebrows, and face, and sometimes trunk. In newborns, it causes a thick, yellow, crusty scalp rash called cradle cap, which seems related to lack of biotin and is often curable. (ICD-10 L21; L21.0)

Less common types
Dyshidrosis
Dyshidrosis (dyshidrotic eczema, pompholyx, vesicular palmoplantar dermatitis) only occurs on palms, soles, and sides of fingers and toes. Tiny opaque bumps called vesicles, thickening, and cracks are accompanied by itching, which gets worse at night. A common type of hand eczema, it worsens in warm weather. (ICD-10 L30.1)

Discoid
Discoid eczema (nummular eczema, exudative eczema, microbial eczema) is characterized by round spots of oozing or dry rash, with clear boundaries, often on lower legs. It is usually worse in winter.