Introduction 

What is leprosy?

Leprosy is a chronic infection caused by bacterial species called Mycobacterium leprae and Mycobacterium lepromatosis.¹ This condition, also known as Hansen disease, changes the normal function of the peripheral nerves and can produce symptoms that alter the skin.¹ These nerves are involved in transmitting signals from the central nervous system around the body, and therefore, this disease can lead to numbness and lack of sensitivity.^1,2 One symptom of leprosy includes ulcers forming predominantly on the legs. which is related to the insensitivity that leprosy causes.³ In leprosy, ulceration is chronic and can cause long-term nerve pain.¹ In addition, these ulcers can have serious consequences, such as amputation and bone infections.³ Therefore, it is important to reduce the chances of ulcers forming in individuals with leprosy, as it can lead to further complications and hospital admissions.⁴ This article will cover how chronic ulcers arise in leprosy patients with the aim of providing guidance for preventing and treating this serious symptom. 

Understanding chronic ulcers in leprosy 

What are chronic ulcers? 

An ulcer describes an abnormal area of the skin that has formed due to a lesion.⁵ Ulcers cause the skin to change from its normal colour, and in leprosy, the ulcers are reported to have a circular shape.³ Ulcers can be accompanied by swelling in the affected region and the discharge of pus from the site.⁶ Some ulcers may only affect the surface layer of skin that it persists on, but, others can alter the tissues and bones below the site of the ulcer.⁶ Chronic ulcers are characterised by hardened and calloused skin around the ulcer with pale skin in the middle of the site.⁶ These ulcers are chronic due to their inability to be permanently resolved after proper treatment has been administered.⁷ This challenge with treating chronic ulcers makes the prevention of this symptom vital for leprosy patients. 

Where do chronic ulcers occur?

 Leprosy tends to cause ulcers on areas of the skin that experience prolonged pressure.³ This links to the loss of sensation that occurs due to leprosy and mostly affects the legs and feet.³ This commonly includes plantar ulcers, which are a term that describes ulcers that form on the underside of the foot.⁷ The prominence of these ulcers on the foot links to high pressure and also the close proximity of bones to the surface of skin.⁷ 

Why do chronic ulcers occur in patients with leprosy? 

When the Mycobacterium leprae bacteria infect the peripheral nerves, they can become damaged.³ Since the peripheral nerves are involved in transmitting signals from the brain to the sensory systems of the body,² when these are impaired, they can cause downstream effects to these areas. This can alter normal movements, sensation and regulation of physiological processes, which can lead to dry skin, muscle weakness and numbness.³ The combination of these features means that the skin could become injured, and an individual would not be aware of any cuts or injuries they have obtained, and could be sites of chronic ulcer formation.⁶ There is also the chance that bacteria can invade the blood vessels and lead to sites of inflammation, tissue death and ulcers.³

How chronic ulcers in leprosy can be prevented? 

Chronic ulcers are a long-lasting symptom that individuals with leprosy can suffer from and are associated with the risk of tissue death and nerve damage.⁴ Therefore, it is key to prevent the onset of ulceration. The formation of ulcers is due to pressure build-up and loss of sensation, primarily in the feet, and therefore, proper care and treatment of this area is advised.⁶ This includes fitting insoles that complement the natural curve of the foot so that pressure is well-spread and balanced.⁶ Other recommendations for the feet can include a metatarsal bar, a support pad that is placed under the ball of the foot and designed to shift weight to the back of the sole.⁶ In addition to these features, it is vital that patients with leprosy wear supportive footwear.⁶ Similarly, the individual should introduce supportive measures and precautionary limits when walking.⁶ This includes only walking suitable distances and checking the feet after walks to examine for injuries.

Prevention of chronic ulcers in individuals with leprosy should also focus on the care of the skin. This involves reducing the chances of injuries to the susceptible areas and checking the skin regularly for cuts or wounds in case these cannot be felt. Due to the lack of sensitivity that leprosy causes, the individual should proceed with caution around hot objects, the risk burning the skin.⁸ Similarly, walking barefoot is highly discouraged for those with leprosy.⁸

Care and management of the skin involves maintaining high levels of hygiene, such that it is advised to wash and dry the feet and toes, keep nails cut short, moisturise the skin and remove dry skin and calluses.⁸ Individuals with leprosy should consult the support of a chiropodist to keep the toes healthy and reduce the risk of ulceration.⁶

How chronic ulcers in leprosy can be treated? 

There is a range of treatment options for individuals suffering from chronic ulcers, depending on the extent of damage to the skin. These target the removal of infection, resolving open wounds and reducing numbness.⁶ Normally, chronic ulcers are addressed with multidrug therapy, which describes the use of more than one medication.⁷

A main treatment option in antibacterial agents is to tackle the bacterial infections that proliferate in cuts and wounds.⁶ Antibiotics can be administered in multiple forms, including oral and topical, with the latter providing the option for directed administration to the ulcer site.⁶

Depending on the extent of the tissue damage that ulcers have caused, it may be necessary for debridement to be performed.⁷ This is a procedure that removes dead or infected skin to promote the healing of healthy skin, normally through surgery. These can then be followed by a skin graft, which introduces uninfected skin to the site of the ulcer to replace the skin that has been removed in debridement.⁷ Orthopedic surgery may also be necessary to correct bony prominences, the presence of bones close to the surface of the skin. This can encourage ulcers to close up and heal.⁷

Conclusion 

Leprosy is an infectious condition that affects the peripheral nerves.1 This alters the feeling of sensation, particularly in the legs and feet.³ As a result of this, these body parts are susceptible to injury and infection, which promotes the formation of ulcers.⁷ In leprosy, these changes to the skin can be chronic and require surgical interventions or long periods of multi-drug therapy to resolve.⁷ Therefore, it is essential to reduce the chances of developing ulcers in patients with leprosy. This involves wearing suitable footwear and foot supports, limiting walking and adhering to hygiene practices and skin maintenance.^6,8

Summary of ulcer prevention approaches 

The key strategies discussed in this article that can help to prevent the formation of ulcers in patients with leprosy include:^6,8 

• Wearing supportive footwear 
• Introducing foot aids such as a metatarsal bar and insoles 
• Reduce the distance of walks 
• Regularly check the skin for injuries 
• Care for the feet by cutting nails and seeing a chiropodist 
• Clean and moisturise the skin