Cutaneous xanthomas

Specialty: Endocrine and metabolic.

• cutaneous lipid plaques
• eruptive xanthomatosis
• cholesterol nodules in the skin

Why it occurs

• Heterozygous or homozygous familial hypercholesterolemia (causing tendon xanthomas in the Achilles and interdigital tendons of the hand, and tuberous xanthomas in the elbows and knees)
• Severe hypertriglyceridemia or type V hyperlipidemia (causing eruptive xanthomas that appear as pruritic yellowish papules on the buttocks and thighs)
• Primary biliary cirrhosis (chronic biliary obstruction increases circulating levels of lipoprotein
• Long-term severe hypothyroidism (thyroid hormone deficiency drastically decreases the expression of hepatic LDL receptors, raising circulating cholesterol)
• Nephrotic syndrome (urinary loss of albumin stimulates massive and reactive hepatic synthesis of lipoproteins)

Initial workup

Complete fasting lipid profile (total cholesterol, triglycerides, HDL, LDL, VLDL); plasma amylase and lipase if abdominal pain is associated; thyroid function tests (high-sensitivity TSH and free T4); complete liver profile including alkaline phosphatase and GGT; estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio; and skin punch biopsy if there are doubts about the histological nature of the plaques (demonstration of lipid-laden foamy macrophages).

Standard management

• Fenofibrate — PPAR-alpha receptor agonist drug that stimulates the activity of lipoprotein lipase, a priority choice in severe hypertriglyceridemia with risk of pancreatitis and eruptive xanthomas
• Atorvastatin — high potency statin to reduce LDL cholesterol and promote gradual regression of tendon and interdigital xanthomas
• Evolocumab — monoclonal antibody inhibitor of PCSK9, indicated in homozygous or heterozygous familial hypercholesterolemia refractory to maximum doses of statins and ezetimibe
• Purified Omega-3 fatty acids — eicosapentaenoic acid at doses of 2-4 grams per day as an adjuvant in the reduction of serum triglycerides