Palmoplantar keratoderma

Specialty: Skin.

• hyperkeratosis of palms and soles
• tylosis
• palmoplantar corneal thickening

Why it occurs

• Familial hereditary keratodermas (mutations in keratin genes, autosomal dominant or recessive inheritance)
• Haxthausen's climacteric keratoderma (development of painful hyperkeratoderma on the palms and heels in postmenopausal women)
• Chronic mycoses ("extensive moccasin ringworm" induced by *Trichophyton rubrum*)
• Chronic exposure to heavy metals such as arsenic (arsenical keratoderma characterized by punctate keratotic papules on palms and soles)
• Paraneoplastic syndrome associated with adenocarcinoma of the esophagus or lung.

Initial workup

Deep skin biopsy with punch of the hyperkeratotic areas for structural histopathological study. Direct examination with 20% KOH and mycological culture of the debris to rule out chronic dermatophytosis. Determination of arsenic levels in urine or hair if there is environmental suspicion. Upper gastrointestinal endoscopy if there is suspicion of concomitant esophageal neoplasia.

Standard management

• 10% or 20% salicylic acid based on Vaseline — high-potency keratolytic designed to peel and soften the thickened stratum corneum
• Urea 40% in cream or ointment — powerful moisturizing and keratolytic agent for localized hyperkeratotic areas
• Acitretin — systemic retinoid of choice to normalize skin keratinization in diffuse or severe hereditary forms, doses of 10 to 25 mg daily orally under strict monitoring of lipid profile, transaminases and reproductive indication
• 0.1% tretinoin cream as a topical nightly adjuvant.