Can severe tinea pedis cause xerosis and fissuring of the heel and plantar surface of the foot?

Yes, severe athlete's foot (tinea pedis) can definitely cause dryness and cracking of the heel and plantar surface of the foot.

Severe tinea pedis commonly presents with fissures and scaling that can involve all areas of the foot, including the heel and plantar surfaces, particularly in the hyperkeratotic (moccasin-type) form of the infection 1.

Clinical Presentation

The guidelines clearly describe that tinea pedis lesions "may involve all areas of the foot but commonly include the fissures and scaling between toes" 1. More specifically:

• Hyperkeratotic (moccasin-type) tinea pedis specifically affects the soles, heels, and lateral sites of the foot 2
• This form is characterized by severe hyperkeratosis (thickening) of the plantar skin 3
• The infection causes scaling, erythema, and fissure formation 4
• When fissures develop, burning and pain typically occur 4

Three Main Clinical Forms

Tinea pedis presents in three primary patterns 5:

1. Interdigital type - affects toe web spaces with maceration and fissuring
2. Vesiculobullous type - presents with vesicles and blisters on soles
3. Hyperkeratotic (moccasin) type - causes extensive dryness, scaling, and cracking of the heel and plantar surface

The hyperkeratotic form is the specific variant that causes the heel and plantar dryness/cracking you're asking about.

Causative Organisms

The predominant causes are Trichophyton rubrum and Trichophyton mentagrophytes 1. T. rubrum is particularly associated with the chronic hyperkeratotic presentation that affects the plantar surfaces and heels 6.

Important Clinical Pitfalls

Do not mistake hyperkeratotic tinea pedis for other conditions:

• It can clinically mimic acquired ichthyosis, severe xerosis, psoriasis, or dermatitis 3
• The diagnosis requires confirmation - clinical accuracy is low 5
• Always perform KOH wet-mount examination or fungal culture to confirm 5
• Periodic acid-Schiff (PAS) staining may be needed to visualize fungal hyphae if biopsy is performed 3

Treatment Implications

The hyperkeratotic form affecting heels and plantar surfaces requires more aggressive treatment than simple interdigital disease 2:

• Should be treated with simultaneous topical AND systemic antifungals 2
• Topical therapy alone is often insufficient for extensive plantar involvement
• Oral terbinafine 250 mg once daily for 1 week, or oral itraconazole 100 mg daily for 2 weeks are effective systemic options 1
• Combined therapy increases cure rates 5

Risk Factors to Consider

Obesity and diabetes are additional risk factors for developing tinea pedis 1, and patients with diabetes have a 59% prevalence of tinea pedis 7. This is particularly important because fissures from tinea pedis can serve as entry points for bacterial infections like β-hemolytic streptococci, increasing the risk of erysipelas 4.