A Durlacher corn, also known as a Lister’s corn in North America, is a specialized type of hard corn (heloma durum) that typically forms on the lateral aspect of the fifth toe, adjacent to the nail. It is named after Lewis Durlacher, a prominent 19th-century British chiropodist who first described the condition. The corn appears as a hardened, painful lesion that can be mistaken for an extension of the toenail or even a second nail, leading to confusion in diagnosis

Unlike typical corns that form on pressure points like the soles or tops of toes, Durlacher corns develop in the lateral nail sulcus—the groove beside the nail—of a rotated or deformed fifth toe. This unique location makes them difficult to distinguish from nail-related issues such as onychophosis (thickened skin around the nail)

Causes and Contributing Factors

The primary cause of Durlacher corns is pressure and friction, much like other types of corns. However, the specific anatomical and biomechanical factors that contribute to their development make them distinct:

• Toe Deformities: The fifth toe is often internally rotated or clawed, creating abnormal pressure against the adjacent nail sulcus. This misalignment is a key factor in the formation of Durlacher corns
• Footwear: Tight or ill-fitting shoes exacerbate pressure on the lateral side of the toe, especially in individuals with toe deformities.
• Gait Abnormalities: Walking patterns that place excessive stress on the outer toes can contribute to corn formation.
• Genetic Predisposition: Some individuals may inherit structural foot traits that make them more susceptible to corns.

Symptoms and Clinical Presentation

Durlacher corns are often painful and can significantly affect mobility. Common symptoms include:

• Localized Pain: A sharp or aching pain on the side of the little toe, especially when wearing shoes.
• Hard, Raised Lesion: A dense, circular area of thickened skin that may resemble a nail fragment.
• Inflammation: Redness and swelling around the corn, particularly if it becomes infected.
• Difficulty Walking: Pain may cause individuals to alter their gait, leading to further biomechanical issues.

Because of its location and appearance, a Durlacher corn may be misdiagnosed as a double nail, a nail deformity, or even a wart. Accurate diagnosis requires a trained podiatrist who can distinguish between nail and skin lesions.

Diagnosis and Differentiation

Diagnosing a Durlacher corn involves a combination of visual examination, palpation, and sometimes dermatological imaging. Key diagnostic steps include:

• Inspection of Toe Alignment: Identifying internal rotation or clawing of the fifth toe.
• Examination of the Nail Sulcus: Determining whether the lesion is part of the nail or a separate cornified structure.
• Debridement: Carefully removing the lesion to assess its depth and origin.
• Differential Diagnosis: Ruling out other conditions such as onychophosis, fungal infections, or keratotic lesions.

Treatment Options

Treatment of Durlacher corns focuses on relieving pain, removing the lesion, and correcting the underlying cause to prevent recurrence. Common approaches include:

Conservative Treatments

• Debridement: A podiatrist may carefully remove the corn using sterile instruments.
• Padding and Offloading: Custom toe pads or orthotics can redistribute pressure away from the affected area.
• Footwear Modification: Switching to wider, more supportive shoes can reduce friction.

Surgical Treatments

In cases where conservative methods fail or the toe deformity is severe, surgical intervention may be necessary:

• Flexor Tenotomy: A procedure to release the tendon causing toe clawing, thereby correcting alignment
• Partial Nail Removal: If the corn is closely associated with the nail, part of the nail may be surgically removed.
• Digital Realignment: Correcting the position of the toe to eliminate pressure points.

Prevention and Long-Term Management

Preventing Durlacher corns involves addressing the root causes of pressure and friction. Long-term strategies include:

• Regular Podiatric Checkups: Monitoring foot health and catching early signs of deformity.
• Proper Footwear: Choosing shoes with adequate toe room and cushioning.
• Toe Exercises: Strengthening and stretching exercises to maintain toe flexibility.
• Orthotic Support: Custom insoles to correct gait and distribute pressure evenly.

Historical and Clinical Significance

The naming of the Durlacher corn pays homage to Lewis Durlacher (1792–1864), who served as the chiropodist to the British royal household. His contributions to foot care laid the foundation for modern podiatry, and the recognition of this specific corn type reflects the evolution of clinical understanding in dermatology and orthopedics.

Though small in size, a Durlacher corn can cause significant discomfort and impact quality of life. Its unique location and association with toe deformities make it a challenging condition to diagnose and treat. Awareness among clinicians and patients is crucial for early intervention and effective management. By understanding the anatomy, causes, and treatment options, individuals can take proactive steps to maintain foot health and avoid the pain associated with this rare but impactful condition.