A patient complains of a painful, cone-shaped, hard lesion on the fifth toe. The nurse identifies this as a corn. What is the primary cause for the development of this condition?

Appeared in: NORCET 1 - 2020

Explanation

A corn (heloma) is a specific type of skin thickening (hyperkeratosis) that forms in response to repeated stress.
The primary cause is external pressure or friction, most commonly from shoes that are too tight or do not fit properly.
This pressure stimulates the epidermis to produce excess keratin, forming a dense, painful, cone-shaped core that presses on underlying nerves.
The location on the fifth toe is a classic site for pressure from footwear.

Option A: A fungal infection (tinea pedis) presents with symptoms like itching, scaling, and maceration between the toes, which is inconsistent with a hard, cone-shaped lesion.
Option C: A viral infection (HPV) causes warts (verrucae), which are distinct from corns. Warts are viral growths and often have small black dots (thrombosed capillaries) on their surface.
Option D: Peripheral vascular disease (PVD) affects blood circulation. While it significantly increases the risk of complications like ulceration and infection from a corn, it does not cause the corn to form.

Visual 1: Diagram - A cross-section of skin showing how a corn's cone-shaped keratin plug presses into the dermis, compared to a callus which is a more diffuse thickening.
Visual 2: Image Comparison - Side-by-side photos of a hard corn on a toe, a plantar wart with its characteristic black dots, and the scaling appearance of athlete's foot.

Clinical Relevance

Nursing practice connection: Use the key finding related to Etiology of corns (heloma) to guide bedside assessment, documentation, and the next nursing action.
Nurses play a crucial role in patient education regarding proper footwear and foot hygiene to prevent corns and other foot problems.
Assessment of a patient's feet is a key nursing responsibility, especially in high-risk populations such as older adults and individuals with diabetes or PVD.
A simple corn can become a serious health issue, leading to ulcers, infection, and potential amputation in patients with compromised circulation or sensation.

How to Approach the Question

Analyze the question's keywords: The description 'painful, cone-shaped, hard lesion on the fifth toe' and the identification as a 'corn' are the key clinical facts.
The question asks for the 'primary cause,' which means you need to identify the direct trigger for the corn's formation.
Evaluate each option based on the pathophysiology of a corn. A corn is a hyperkeratotic lesion caused by mechanical stress.
Eliminate Option A (fungal) and Option C (viral) as they describe infectious processes with different clinical presentations (itching/scaling for fungal, black dots for viral warts).
Eliminate Option D (PVD) because it's a condition that worsens outcomes (a risk factor for complications) rather than causing the initial lesion.
Conclude that Option B (chronic pressure/friction) directly explains the mechanical stress that leads to the protective skin thickening characteristic of a corn.

Concept Tested & Keywords

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Practise the full NORCET 1 - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.