Intertriginous Xanthomas: Clues to Homozygous Familial Hypercholesterolemia

A 17-year-old female, born to nonconsanguineous parents presented with yellowish-brown plaques over major flexors for the past 10 years, along with nodular swellings over dorsal fingers and elbows. Over lower limbs, there were extensive barely raised yellow plaques that became more elevated, rough, and dark brown over pressure areas (buttocks, knees) and flexors [Figure 1]. Similar plaques were present over the periocular area, along with arcus senilis [Figure 2]. Blood investigations revealed very high low-density lipoprotein-cholesterol (LDL-C) levels (561 mg/dL), fulfilling the clinical criteria for phenotypic homozygous hypercholesterolemia (HoFH).[1] She was referred to the endocrinology department, started on rosuvastatin 40 mg, screened, and advised lipid levels in all immediate family members. She was found to have mild carotid intimal thickening and was advised regular follow-up. The family could not afford genetic testing.Figure 1: Intertriginous xanthomas in a patient with familial homozygous hypercholesterolemia, presenting as yellow discrete and coalescing papules and plaques over the bilateral cubital fossae (a), and popliteal fossae, in continuation with plane xanthomas over the posterior thighs, presenting as extensive orangish-yellow, barely raised plaques (b). Similar plaques were also present over groins and knees (c), over buttocks and posterior thighs (d). Darker, rougher, and elevated intertriginous xanthomas were present in the interdigital spaces, along with dome-shaped yellow nodules interphalangeal joints, suggestive of tuberous xanthomas (e)Figure 2: Plane xanthomas over the periorbital area, presenting as barely raised yellow plaques, along with premature arcus senilis, presenting as a yellowish-brown ring over the margins of the cornea, in a patient with homozygous familial hypercholesterolemiaLDL-C levels >400 mg/dL, along with cutaneous and tendon xanthomas before 10 years of age are part of the clinical diagnostic criteria of HoFH.[1] Although tendinous xanthomas are more common, seen in 40%–50% of cases; intertriginous xanthomas, seen rarely, are considered pathognomonic of HoFH.[2] Certain disorders like sitosterolemia can have a similar profile as HoFH, but have different genetics and management, so should be excluded by gas chromatography or genetic analysis. HoFH patients should undergo extensive cardiovascular imaging, aggressive lipid-lowering therapy, and lifestyle changes, along with reverse cascade screening of their family members. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.