Introduction

What is a pyogenic granuloma?

A pyogenic granuloma (PG) is a benign (noncancerous) growth made of blood vessels. PGs usually look like red lumps that bleed easily; however, they occasionally present as wider, flat patches. The term pyogenic granuloma originated from the inaccurate belief that the lesion was caused by infection and pus formation (pyogenic means pus-forming). Even though the term PG is still used, the scientifically accurate term is lobular capillary hemangioma.¹

PGs usually develop on the skin or mucous membranes, such as inside the mouth. In adults, PGs most frequently present on the trunk or upper extremities and, sometimes, on the head or neck. In children, the lesions are most commonly seen on the head and neck, followed by the extremities. PGs can occasionally develop under or around the nails; when multiple PGs appear around the nails, it is usually associated with certain medications. During pregnancy, there is an increased likelihood of PGs forming in the inner lining of the cheeks or the gums.¹

Even though they are benign, PGs are often removed, as they can easily bleed, become cosmetically bothersome, or be uncomfortable. It is important to note that even after removal, PGs could come back and should be monitored.¹

What causes pyogenic granulomas?

Even though the exact cause of PGs is often difficult to pinpoint, several factors and mechanisms can be implicated in their development:

Trauma or injury

After a minor injury, the healing process involves the formation of new tissue and blood vessels, referred to as reactive granulation tissue; this is a normal process; however, the tissue can grow excessively and form a PG. To that extent, PGs originate from prior trauma or injury in up to 7% of cases.¹

Hormonal changes 

Hormonal changes appear to play a role in the development of PG, particularly during pregnancy; thus are referred to as granuloma gravidarum or pregnancy tumour. Even though more studies are needed, it is hypothesised that some sex hormones, such as oestrogen, could increase the inflammatory response in gum tissue in the mouth, particularly during pregnancy.^1,2

Medications

Some types of PGs have been associated with the use of certain medications. In particular, PGs around the nails are attributed to medication use in about 30% of cases. Some of these medications include birth control pills, cancer treatment drugs including gefitinib and capecitabine, anti-rejection drugs prescribed after an organ transplant, such as mTOR inhibitors, medications used for auto-immune diseases, and retinoids (prescribed for severe acne or skin conditions).^1,2

Treatment of pyogenic granuloma

Despite being benign, PG is often treated to avoid the inconvenience of a frequently bleeding lesion or for cosmetic reasons. There are a variety of treatment options available, including surgical and nonsurgical methods, all with varying amounts of efficacy and recurrence rates.

Surgical removal

Complete surgical excision 

Surgical excision is the preferred treatment method when the PG is located in an inconspicuous area of the body where a small scar would not be a concern. Surgical excision is performed under local anaesthesia and allows for the pathological analysis of the tissue removed. The whole PG is removed; therefore, surgical excision results in the lowest rate of recurrence. In 98% of cases, surgical excision allows the complete removal of the PG in just one session.^1,3

Shave excision or curettage, and cauterisation 

Shaving off the PG with a surgical blade, or scraping it with a curette (small, spoon-shaped tool), followed by cauterisation of the wound, is sometimes used to achieve better cosmetic results. However, there is a significantly higher risk of recurrence with this method compared to a full surgical excision.^1,3 

Laser therapy

Various types of lasers have been used alone or in combination with a surgical intervention to remove PGs. While the success rate depends on the lesion and the type of laser used, a study has shown that a CO₂ laser, under specific conditions, was able to achieve a 98% success rate in one session.³

Cryotherapy and cautery

Cryotherapy is another treatment option for PG, where liquid nitrogen is used to freeze and remove the lesion. Even though there are little to no side effects associated with this method, it can take an average of one to four sessions, and offers a lower resolution rate compared to surgical methods.^1,2,4

Smaller PGs can be treated with cautery. Electrocautery is a method in which an electrical current is used to burn the lesion. Electrocautery can be used alone or in combination with surgical methods; however, the rate of recurrence can be higher than when performing a complete surgical removal. Chemical cauterisation with silver nitrate is another nonsurgical option that can be used alone or in combination with another method.^1,5,6

Medication

Medication-based treatments are generally not the first treatment recommended; however, they can be used as an alternative in certain situations. These include various topical treatments such as beta-blockers, corticosteroids, retinoids, and phenols. The direct injection of some of these medications into the PG has been reported with limited efficacy. Due to their non-invasive nature, medication-based treatments could be favoured in children to avoid a potentially traumatic surgical intervention.^1,7

Why do some pyogenic granulomas come back after removal?

Incomplete excision

PGs are not fully encapsulated, meaning they do not have clear margins; therefore, it can be difficult to identify the boundaries while performing the excision. For this reason, shaving and curettage are more likely to lead to a recurrence of PG. It is recommended to perform an excision with wider margins to minimise the chances of recurrence. Incomplete excision is the most common cause for the recurrence of PGs.^1,6

Persistent underlying cause

Local irritation or trauma 

Constant irritation or trauma can lead to the appearance of PGs and their recurrence. For example, the gums are a common location for PGs. Plaque buildup, food particles stuck near the gums, poor dental work, or small injuries can irritate the gums, causing a PG to form during the healing process. When removing a PG from the gums, it is important to clean nearby teeth carefully to get rid of any buildup that could be irritating to avoid recurrence.⁸

Hormonal factors

Hormones like oestrogen and progesterone, which increase during pregnancy, are known to affect both the development and recurrence of PGs, sometimes called "pregnancy tumours" when they affect pregnant women. PGs could affect small blood vessels, the immune system, and gum tissue cells, leading to increased inflammation and more leaky blood vessels, which can cause the lesions to grow or come back. The use of oral contraceptives can be a contributing factor to the appearance and recurrence of PGs. The rate of recurrence of PGs treated during pregnancy is higher; therefore, it is recommended to remove the lesion after childbirth when possible.^8,9,10

Medications 

As mentioned previously, certain medications can increase the chances of a PG forming. Unless these are discontinued, which is not always possible, PGs are more likely to come back after removal.¹

How to manage recurrent pyogenic granulomas

To manage recurring PGs, it is essential to consider the cause of the recurrence and select an appropriate treatment strategy. The main cause of recurrence is incomplete excision; therefore, the most important strategy to keep a PG from coming back after initial treatment is to ensure complete removal; this is achieved by ensuring that surgical removal includes enough margins, usually recommended at around 2mm of healthy tissue around the PG. Additionally, it is helpful to send a biopsy of the removed tissue to be analysed under a microscope, to ensure the presence of healthy margins.^6,11

As mentioned previously, underlying factors such as local irritation, hormonal factors, and some medications can increase the rate of recurrence. These situations should be carefully considered by the treating physician. While changes in medication and hormonal factors can be more challenging to address, a source of local irritation can usually be fairly easily removed. Due to the propensity of PGs to recur, patients should have thorough conversations with their healthcare provider to determine what caused the PG in the first place. Furthermore, long-term follow-up after removal is recommended.⁸

Summary

Pyogenic granulomas (PGs) are benign vascular growths that usually appear on the skin or mucous membranes. While they are noncancerous, PGs can bleed easily and are commonly removed for comfort or cosmetic reasons. Recurrence of PGs after removal is, unfortunately, quite common. The most frequent cause of recurrence is incomplete excision due to the lesion’s poorly defined boundaries. Ensuring adequate surgical margins, typically around 2 mm of surrounding healthy tissue, can significantly reduce the chance of regrowth.

Other contributing factors include persistent local irritation (such as poor dental hygiene or dental work), hormonal influences (especially during pregnancy), and certain medications (including cancer therapies or oral contraceptives). While medication-based treatments and nonsurgical methods such as laser therapy, cryotherapy, or cauterisation can be effective in some cases, they generally have higher recurrence rates compared to complete surgical excision.

To effectively manage and prevent recurrence, identifying and addressing the underlying cause is key. Long-term follow-up is advised, and the timing of treatment, particularly in pregnancy-related cases, should be carefully considered to lower recurrence risk.