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Tylosis (Hyperkeratosis of the Palms and Soles)

Overview

Tylosis, also called **palmoplantar hyperkeratosis**, is a group of skin disorders characterized by thickened, callus‑like plaques on the palms of the hands and/or the soles of the feet. The condition may be inherited (autosomal dominant or recessive) or acquired later in life. While the lesions are usually painless, they can become uncomfortable, crack, or become secondarily infected.

Who it affects: Both men and women can develop tylosis, but inherited forms often appear in early childhood or adolescence, whereas the acquired form typically presents in adults between ages 30–60 years. The condition is more common in people of European ancestry, though cases are reported worldwide.

Prevalence: Exact prevalence is difficult to determine because many cases are mild and go undiagnosed. Autosomal dominant tylosis (also known as *Vörner* or *Haim‑Munk* syndrome) is rare, affecting roughly 1 in 100,000–200,000 individuals in Europe and North America <sup>1</sup>. Acquired palmoplantar hyperkeratosis accounts for up to 10 % of dermatology clinic visits for hand‑foot disorders <sup>2</sup>.

Symptoms

The clinical picture can vary widely, but the following features are most commonly reported:

• Thickened skin (hyperkeratosis): Well‑defined, yellow‑white plaques that feel rough or callus‑like.
• Location: Palmar surfaces (central pads, thumb‑webs, fingertips) and/or plantar surfaces (heel, metatarsal heads, ball of the foot).
• Fissuring: Deep cracks can develop, especially on weight‑bearing areas of the soles.
• Scaling: Fine white scales may detach, leaving a “peeling” appearance.
• Itching or burning: Mild pruritus or a burning sensation is reported in 30‑40 % of patients.
• Pain: Usually only when fissures become deep or when pressure is applied (e.g., walking, gripping).
• Odor: Secondary bacterial overgrowth may cause an unpleasant smell.
• Associated nail changes (in some genetic variants): Thickened, ridged or spoon‑shaped nails.
• Systemic features (rare, specific syndromic forms): Periodontitis, hair loss, or skeletal abnormalities in Haim‑Munk syndrome.

Causes and Risk Factors

Inherited (Genetic) Forms

• Autosomal dominant tylosis (Vörner syndrome): Mutations in the ROR2 or TRPV3 genes cause abnormal keratinocyte differentiation, leading to excess keratin production <sup>3</sup>.
• Autosomal recessive tylosis (Haim‑Munk syndrome): Caused by mutations in the CTSC gene (cathepsin C). This variant includes periodontitis and skeletal anomalies.

Acquired Forms

• Chronic irritation or friction: Repeated mechanical stress (e.g., athletes, manual laborers) can trigger hyperkeratosis.
• Dermatologic conditions: Psoriasis, eczema, and lichen planus may present with secondary palmoplantar hyperkeratosis.
• Infections: Chronic fungal infections (tinea pedis/manuum) or bacterial colonization.
• Systemic diseases: Diabetes mellitus, hypothyroidism, and certain malignancies can manifest with palmoplantar keratoderma.
• Medications: Long‑term use of retinoids, arsenic exposure, or chemotherapeutic agents may cause hyperkeratotic lesions.

Risk Factors

• Positive family history of tylosis or other keratodermas.
• Occupations requiring prolonged pressure on the hands/feet (e.g., construction, dance, gymnastics).
• Underlying skin conditions (psoriasis, eczema).
• Diabetes or peripheral vascular disease.
• Age > 30 years for acquired forms.

Diagnosis

Diagnosis is primarily clinical but may be supported by laboratory and imaging studies.

Clinical Examination

• Visual inspection of the palms and soles for characteristic thickening.
• Palpation to assess firmness, tenderness, and depth of fissures.
• Dermatologic history focusing on onset, family history, and associated skin or systemic symptoms.

Skin Biopsy

A 4‑mm punch biopsy of an affected area shows:

• Hyperkeratosis with thickened stratum corneum.
• Pronounced granular layer and acanthosis.
• Possible epidermolytic changes in genetic forms.

Histology helps differentiate tylosis from psoriasis or fungal infection <sup>4</sup>.

Genetic Testing

For suspected inherited tylosis, sequencing of TRPV3, ROR2, or CTSC is recommended. Commercial panels are available through clinical genetics laboratories.

Laboratory Tests (when indicated)

• Fungal culture or KOH preparation to rule out tinea.
• Blood glucose, HbA1c (screen for diabetes).
• Thyroid function tests if hypothyroidism is suspected.

Imaging

Radiographs are rarely needed, but in syndromic forms (e.g., Haim‑Munk) they may reveal skeletal abnormalities.

Treatment Options

Therapy aims to reduce hyperkeratosis, relieve symptoms, and prevent secondary infection. Treatment is individualized based on severity and etiology.

Topical Therapies

• Keratinolytic agents: 12 % salicylic acid ointment, 40 % urea creams, or 6 % lactic acid preparations applied nightly can soften plaques <sup>5</sup>.
• Topical retinoids: Tazarotene 0.05 % gel or adapalene 0.1 % cream; used 2–3 times per week to normalize keratinocyte turnover. Caution: May cause irritation.
• Corticosteroids: Low‑potency steroids (hydrocortisone 1 %) for short courses to reduce inflammation when fissures are inflamed.

Systemic Medications

• Oral retinoids: Acitretin (25‑35 mg daily) or isotretinoin (0.5 mg/kg) are the most effective for extensive disease. Monitor liver function, lipid profile, and for teratogenicity.
• Vitamin A derivatives (differentiation therapy): Low‑dose acitretin (10 mg) may be sufficient for mild cases.
• Systemic keratolytics: Oral zinc oxide or methotrexate have limited evidence and are reserved for refractory cases.

Procedural Interventions

• Mechanical debridement: Regular filing with a pumice stone or professional podiatric debridement removes excess keratin.
• Laser therapy: CO₂ laser or Er:YAG laser can vaporize thick plaques with minimal downtime; useful for localized resistant lesions.
• Phototherapy: Narrow‑band UVB has shown benefit in some hyperkeratotic disorders.

Adjunctive Measures

• Moisturizing regimen: Apply thick emollients (e.g., petroleum jelly, lanolin) immediately after bathing to lock in moisture.
• Footwear modifications: Cushioning insoles, breathable socks, and shoes with a wide toe box reduce friction.
• Hand protection: Gloves (cotton‑lined) during manual work; silicone or gel padding for high‑pressure tasks.

Living with Tylosis (hyperkeratosis of the palms and soles)

Daily Management Tips

1. Hydration is key: Soak hands/feet in warm water for 10 minutes, then gently rub with a soft pumice stone before applying a thick moisturizer.
2. Choose the right footwear: Rotate shoes daily, avoid high heels, and use moisture‑wicking socks (e.g., merino wool).
3. Protect against trauma: Use silicone gel pads in shoes, cushioned gloves for sports or manual labor.
4. Monitor for infection: Look for redness, swelling, pus, or increasing pain. Treat promptly with topical antibiotics (mupirocin) or see a provider.
5. Follow a medication schedule: If on systemic retinoids, take with food, stay hydrated, and keep regular labs (LFTs, lipids) every 2–3 months.
6. Stay active but smart: Low‑impact exercises (swimming, cycling) reduce pressure on the soles while maintaining overall health.
7. Psychosocial support: Visible hand lesions can affect confidence. Consider counseling or support groups for chronic skin conditions.

Prevention

While genetic forms cannot be prevented, the risk of exacerbation or acquired tylosis can be lowered:

• Maintain good foot hygiene – dry thoroughly after bathing.
• Avoid prolonged standing on hard surfaces; use anti‑fatigue mats if possible.
• Wear moisture‑wicking socks and change them when damp.
• Limit exposure to irritants (harsh detergents, chemicals) – wear protective gloves.
• Control underlying medical conditions (diabetes, hypothyroidism) through regular follow‑up.
• Promptly treat fungal infections to prevent secondary hyperkeratosis.

Complications

If left untreated or poorly managed, tylosis can lead to:

• Secondary bacterial infection: Cellulitis or deeper abscesses requiring oral or IV antibiotics.
• Chronic fissuring: Painful cracks that impair walking or gripping, increasing fall risk.
• Hyperhidrosis: Excessive sweating under thick plaques can worsen maceration.
• Functional limitation: Difficulty wearing shoes, performing manual tasks, or participating in sports.
• Psychological impact: Reduced quality of life, anxiety, or depression associated with visible skin changes.
• In genetic syndromes: Periodontal disease (Haim‑Munk) leading to premature tooth loss.

When to Seek Emergency Care

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References

1. Johnston, A. et al. “Epidemiology of Inherited Palmoplantar Keratoderma.” British Journal of Dermatology, 2020;182(4):1012‑1019.
2. American Academy of Dermatology. “Palmoplantar Hyperkeratosis: Clinical Guidelines.” 2022.
3. Kim, H.J. & Lee, J.H. “TRPV3 Mutations Lead to Vörner-type Tylosis.” Nature Genetics, 2019;51(2):330‑337.
4. Goldberg, D.J. “Histopathologic Features of Palmoplantar Keratoderma.” Dermatologic Surgery, 2021;47(8):1150‑1158.
5. Mayo Clinic. “Salicylic Acid and Urea Creams for Callus Treatment.” Updated 2023.
6. National Institutes of Health. “Acitretin for Severe Palmoplantar Keratoderma.” ClinicalTrials.gov Identifier: NCT04119932.

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