Bunion

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

A bunion, known technically as hallux valgus, is a bony bump on the side of the foot at the base of the big toe. Bunions develop slowly as pressure on the joint at the base of the big toe causes the toe to move out of place, leaning inward toward the second toe. Because this joint carries a lot of weight during activities like standing and walking, bunions can cause foot pain, stiffness, redness, and swelling. Calluses may form where the big toe and second toe rub together or on the ball of the foot. Unless they are treated, bunions get worse over time, and it may become difficult to wear regular shoes or walk without pain. Bunions can occur in one or both feet.

In most cases, bunions develop in adulthood. Rarely, children may be born with bunions (known as congenital hallux valgus) or develop them later in childhood (juvenile or adolescent hallux valgus).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The causes of bunions are unclear, although scientists suspect that both inherited and lifestyle factors contribute to their development. Studies suggest that congenital and juvenile hallux valgus tend to be related to joint deformities with a genetic cause. Little is known about the genetic contribution to bunions that occur later in life, and no specific genes involved in the development of bunions have been identified.

For bunions that appear in adulthood, inherited factors related to the shape and structure of the foot and the way the foot moves (foot mechanics) likely influence a person's risk of developing the condition. It has long been suggested that wearing ill-fitting shoes are another significant risk factor, specifically shoes that are too tight, shoes with high heels, or shoes with a narrow toe box. Research suggests that poorly fitting shoes probably do not cause bunions, but they may make bunions develop earlier or worsen more quickly in people with an underlying susceptibility.

Other risk factors for bunions include inflammatory diseases (such as rheumatoid arthritis), osteoarthritis, and flat feet (pes planus). Bunions are also a feature of several rare genetic syndromes that affect bone development, including Chitayat syndrome and fibrodysplasia ossificans progressiva.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Bunions are a complex condition without a clear pattern of inheritance. Many affected individuals have multiple family members who are also affected. The risk of developing bunions is greater for first-degree relatives of affected individuals (such as siblings or children) as compared to the general public.

When bunions occur as part of a genetic syndrome, this feature follows the inheritance pattern of the syndrome.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Bunions are a very common foot disorder, affecting about a third of adults in the United States. The prevalence of bunions increases with age. They are more common in women than in men, likely because of differences in foot anatomy, footwear, and genetic influences.

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Rheumatoid arthritis

Inflammatory changes in the synovial membranes and articular structures with widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, as well as atrophy and rarefaction of bony structures.

Osteoarthritis

Degeneration (wear and tear) of articular cartilage, i.e., of the joint surface. Joint degeneration may be accompanied by osteophytes (bone overgrowth), narrowing of the joint space, regions of sclerosis at the joint surface, or joint deformity.

Hallux valgus

Lateral deviation of the great toe (i.e., in the direction of the little toe).

Pes planus

A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced.

Foot pain

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the foot.

Which doctor should you see?

The suggested department for discussing Bunion is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.