Eruptive Xanthomas

Xanthoma is a skin condition which may affect various parts of the body, depending on which of several subtypes of the condition is extant. The condition is subtyped based on the location of lesions and their development cycle, and presentation of symptoms will differ according to subtype.

Xanthelasma palpebrum is the most common form of xanthoma, and consists of the formation of symmetrical papules or plaques which are velvety, soft and yellow in color. Lesions typically form on the eyelids, and begin as small bumps with grow over a period of months. Tuberous Xanthomas consist of firm yellow-red nodules which form in areas which experience pressure, such as the elbows, heels, buttocks or knees. Lesions are typically painless, and may coalesce into multi-lobed masses. Tendinous Xanthomas develop on the hands, feet, and along the Achilles tendon, and consist of slowly growing nodules which are subcutaneous. Eruptive Xanthomas consist of crops of small yellowish-red papules, typically forming on the buttocks, legs, arms and shoulders, though they may appear anywhere. Lesions may be accompanied by tenderness and itching, and are typically self-resolving. Plane Xanthomas consist of flat patches or papules which may occur on any area of the body, and are associated with a specific type of lipid increase in the blood. Diffuse plane xanthomatosis is a rare type of histiocytosis associated with abnormal antibodies, and presents as large plaques which are yellowish-red in color and appear on the face, neck buttocks, chest and in the natural folds of the skin. Xanthoma disseminatum is also a rare form of histiocytosis, which is accompanied by lesions which are similar in appearance to Xanthomas. The condition consists of the formation of hundreds of small bumps on the face and torso, armpits and groin. Lesions are yellow-brown or reddish-brown in color, and may coalesce into large areas of thickened skin. In some cases, lesions may form on mucosal surfaces such as the airway or eyes, and internal organs may also become involved.

Xanthomas are caused by buildups of fat cells in the immune cells of the skin, or in rare cases under the subcutaneous fat layer. This buildup is typically associated with an underlying systemic condition such as diabetes mellitus or hypothyroidism, or genetic defects such as primary hyperlipoprotenemia, which cause elevated lipid or lipoprotein levels in the bloodstream.

Differential Diagnosis (Other conditions with similar appearance)

Amyloidosis
Juvenile xanthogranuloma (Nevoxanthoendothelioma)
Lipoid Proteinosis
Necrobiosis lipoidica
Cerebrotendinous Xanthomatosis
Sarcoidosis

Xanthomas are typically diagnosed based on the characteristic appearance of the affected area. Blood and urine tests will be performed to confirm the diagnosis and to rule out similar appearing conditions.