How do a corn (heloma) and a bunion (hallux valgus) differ?

Corns and Bunions Are Completely Different Foot Conditions

A corn (heloma) is a localized area of thickened skin with a hard keratin plug that causes pain, while a bunion (hallux valgus) is a structural bone deformity where the big toe deviates laterally and the first metatarsal bone deviates medially. 1, 2

Key Anatomical and Pathological Differences

Corns (Heloma)

• Corns are purely skin lesions consisting of hyperkeratotic tissue with a central nucleus or plug of keratin that extends downward in a cone-shaped point 2, 3
• They develop as a physiologic response to chronic excessive pressure or friction on the skin, representing localized mechanical hyperkeratosis 4
• Patients describe the pain as "walking on a small stone or pebble" due to the central core pressing into deeper tissues 2, 3
• Location: Typically found on tips of toes, underneath metatarsal heads on weight-bearing surfaces, or between toes (soft corns/heloma molle) 2, 3

Bunions (Hallux Valgus)

• Bunions are structural bone deformities characterized by lateral deviation of the great toe combined with medial deviation of the first metatarsal bone (metatarsus primus varus) 1, 5
• This is a three-dimensional skeletal malformation of the first ray, not just a skin problem 6, 7
• The visible "bump" is the medially prominent first metatarsal head, which may develop secondary pressure points and shoe conflict 5
• Location: Always involves the first metatarsophalangeal joint 7, 5

Clinical Significance in High-Risk Patients

Both Are Risk Factors But Different Mechanisms

• Bunions are classified as foot deformities that increase plantar foot pressures and ulceration risk through abnormal biomechanics 1
• Corns are classified as preulcerative lesions that directly precede ulcer formation in at-risk patients 1
• In diabetic or PAD patients, bunions place patients in moderate-to-high risk categories requiring foot specialist referral every 1-3 months 1

Treatment Approaches Are Fundamentally Different

Corn Treatment (Reversible with Conservative Care)

• Primary treatment: Professional debridement/paring by podiatrist to remove the keratin plug 3, 8
• Adjunctive therapy: Topical keratolytics (salicylic acid 15-26%, urea 10%) applied after debridement 8
• Prevention: Pressure redistribution through proper footwear and padding 8, 4
• Corns disappear completely when the causative mechanical forces are removed 4

Bunion Treatment (Requires Structural Correction)

• Conservative treatment cannot correct the deformity but may control symptoms through wider shoes, orthoses, and physiotherapy 7, 5
• Definitive treatment requires surgery when conservative measures fail, involving bony realignment procedures (osteotomies), soft tissue realignment, or arthrodesis 9, 7
• Surgical options are selected based on deformity severity, joint degeneration, and bone anatomy 7
• Post-operative management includes corrective dressings, protected weight-bearing, and 6-7 weeks for bone union 6, 7

Common Clinical Pitfall

Bunions can cause secondary corns due to the altered foot mechanics and abnormal pressure distribution they create 1. A patient may present with both conditions simultaneously—the bunion being the underlying structural deformity and the corn being a secondary consequence of that deformity. In such cases, treating only the corn provides temporary relief, but recurrence is inevitable unless the bunion deformity is addressed 4.

Risk Stratification Implications

• Patients with bunions alone (without neuropathy or PAD) require examination every 3-6 months 1
• Patients with corns/calluses in the presence of loss of protective sensation or PAD require examination every 1-3 months and immediate foot specialist referral 1
• Both conditions mandate therapeutic footwear in high-risk patients to prevent ulceration 1