Overview

A Pyogenic Granuloma (PG) is a common benign tumour that often appears on the lips, hands, face or mucous membranes (nostrils, gums, palate). PG manifests as a red nodule formed due to the excessive growth of small blood vessels (capillaries) under the skin.¹ 

Although PG is usually painless, it can bleed spontaneously and frequently, which can interfere with a patient’s daily activities. Hence, a prompt and accurate diagnosis is essential. Dermatoscopy is a fast, non-invasive imaging technique for diagnosing skin conditions such as PG. By acting as a magnifying glass under the skin, dermatoscopes capture images of the internal structures of a skin lesion, revealing patterns that aid in diagnosis.² 

Understanding pyogenic granuloma

Common signs and symptoms 

There can be several indicators for Pyogenic Granuloma, including the anatomical location of the lesion. PGs, which manifest as soft bumps on the skin, are more likely to appear on certain regions of the body, primarily on the skin or on mucous membranes. Common areas for this lesion include the head and neck areas, under the fingernails and in the oral cavity (especially on the gums).

Here are some of the signs that a skin lesion might be a case of PG:

• Red and occasionally blue colouring 
• Moist, glistening appearance
• Painless to the touch
• Rapid growth 
• Spontaneous bleeding, or bleeding following minor traumas 
• Ulceration

A PG can vary in size and texture and can be either smooth or bumpy to the touch. It can also present as a solitary nodule or, more rarely, as a cluster of nodules in one area.^1,3

What causes it

The medical community is still unsure of the exact causes of PG but recognises that several factors can predispose a patient to PG.³ Certain medical conditions and medications can create a favourable environment for small capillaries to grow quickly, forming these nodules. PG is a potential side effect of the following medications:

• Calcineurin inhibitors
• Antiretrovirals 
• Topical retinoids 
• Immunosuppressants 

Hormonal changes related to pregnancy and puberty, particularly estrogen and progesterone levels, may also cause PG.¹ Although PG is known to occur in patients of any age and gender, for AFAB (assigned female at birth) people, the chances of PG may increase in the second decade of life and during pregnancy.⁴ Pyogenic granulomas occurring during pregnancies are sometimes uniquely referred to as pregnancy granulomas, pregnancy epulis or pregnancy tumours.

In a minority of cases (7%), a PG can be attributed to minor local traumas, such as superficial wounds, infections or vascular malformations.¹

Commonly confused conditions

PG can mimic other similar vascular tumours. Examples of confused conditions include: 

• Malignant melanoma
• Basal cell carcinoma 
• Glomus tumour

The risks of incorrect diagnosis make it extremely important to develop tools that enable thorough evaluations of skin lesions. An accurate and efficient diagnosis ensures that the most effective clinical management plan is implemented to treat the condition. Dermatoscopy offers a quick method to analyse a skin disease and rule out some of the mentioned confused conditions.^5,6

What is dermatoscopy?

Dermatoscopy, also known as dermoscopy, is a simple yet powerful non-invasive imaging technique used in diagnosing skin lesions and other dermatological disorders. Thanks to its size, affordability, and ease of use, dermatoscopy has become a common complementary method for evaluating skin conditions such as skin cancers, dermatoses, and disorders of the scalp, hair, and nails. 

By placing the dermatoscope on the area of interest, a doctor can obtain a magnified image of the internal structure of a lesion, extending up to a few millimetres in depth. Looking at a lesion below the surface layer of the skin reveals important characteristics, such as colour patterns and vascular structures, that can help in the diagnostic process.²

How does it work?

A dermatoscope is a simple device made up of a light source, a magnifying lens, a contact plate, and a power supply. The light source illuminates the skin beneath the surface while the magnifying lens allows one to visualise the small structures in the skin. 

Usually, light reflects off the skin almost entirely, with very little penetrating the outermost layer of the skin. Traditional dermatoscopy addresses this issue by directing the light onto a gel in contact with the skin, which reduces the scattering of the light. The light can then shine through the outermost layer of the skin, allowing the lens to focus on deeper layers of the skin. This technique, known as transillumination, enables the dermatoscope to capture clearer images of subcutaneous features, revealing patterns and vascular structures crucial for diagnosis. 

Transillumination is common in many other areas of medicine, such as paediatrics and dentistry, and is used to observe the internal state of organs and even caries.^2,7

Why dermatoscopy is valuable in skin diagnosis

Like many other imaging techniques, dermatoscopy enables doctors to assess the condition of an organ without the need for surgery or biopsy. The dermatoscope reveals the structure of the dermal lesion, without the need for invasive or semi-invasive procedures, which can be time-consuming, stressful, and might require a specialist referral. Dermatoscopy enables a rapid diagnosis, reducing patient waiting times, preventing the use of unnecessary medications, and ensuring prompt treatment of the disease. 

Despite its usefulness, dermatoscopy does not eliminate the need for other diagnostic techniques. In cases where PG exhibits similar features to other diseases, and is hard to differentiate visually, biopsies are still likely to be performed. For PG, especially, once the nodule is removed, it is usually sent for analysis to validate the original diagnosis.  

New methods in dermatoscopy 

Tools for dermatoscopy come in various forms, and technological advancements have enabled increasingly accessible designs with unique features for different contexts. Newer generations of dermatoscopes incorporate polarising light filters that don’t require direct contact with a gel or the skin. The polarising filters tune out any scattered light and only keep the small fraction of light that manages to penetrate the skin.⁷ This tool reaches deeper points in the skin and results in higher-definition images compared to traditional nonpolarized dermatoscopes. 

What dermatoscopy reveals in pyogenic granuloma

Key features visible under the dermatoscope

Dermatoscopy is a useful technique in the diagnosis of PG. A recent study that analyses over one hundred confirmed cases of PG via dermatoscopy reveals that some common features of the lesion are: 

• Reddish or red-whitish homogeneous area
• White ring-like border (white collarette)

And, in around half of PG cases:

• Straight white lines crossing the lesion
• Crusts or ulcerations
• Visible blood vessel structures

These features, taken in isolation, are not 100% specific to pyogenic granulomas: many of these patterns also arise in melanomas, carcinomas and other vascular lesions. However, combinations of these features appearing in the skin lesion can rule out tumours that are commonly confused with PG. For example, while reddish homogeneous areas are common in a wide range of skin diseases, a red area surrounded by a white collarette, or a red area with white rail lines, is highly specific to PG.⁶ This doesn’t mean all cases of PG will exhibit these traits, but rather that skin lesions that do have these combinations of features are highly likely to be PGs. 

Limitations of using dermatoscopy in diagnosing PG

Due to its noninvasive nature, dermatoscopy is a relatively harmless and low-risk diagnostic technique. However, there are a few things to be kept in mind that might interfere with a patient’s health if not addressed correctly: 

• Potential for misdiagnosis: As mentioned earlier, PG can mimic many other diseases, including cancerous tumours. A dermatoscopic inspection might not be enough to rule out other diagnoses. While this technique can ensure fast results, medical experts still suggest biopsies of PG once removed⁶
• Risk of cross-infection: Dermatoscopy is not only used to examine non-infectious lesions, such as PG, but also for fungi, verrucae and other contagious diseases. Even with a decontamination protocol, lenses are likely to preserve DNA from previous inspections, which can lead to a transfer of an infection from one patient to another.⁸ Polarised dermoscopy is a useful solution to this, thanks to its no-skin-contact method
• Interpretation of artefacts: The presence of hair, dust and other particles on the skin or the dermatoscope lens can generate fictitious patterns, leading to the misinterpretation of certain images. However, careful disinfection practices and clinical expertise greatly reduce the risk of this type of issue arising²

Summary

While pyogenic granuloma is a benign tumour with a straightforward treatment, its dermatoscopic similarity to other potentially severe conditions makes accurate diagnosis critical. Dermatoscopy is a fast, non-invasive, and highly effective method to support clinical evaluations, providing detailed visuals that can help distinguish PG from other lesions and tumours. Dermatoscopic analysis of PG reveals features specific to the disease, including reddish homogeneous areas, white collarettes, and linear white streaks, which are highly indicative when assessed in combination. 

As new technology continues to improve the diagnostic power of dermatoscopy, this tool’s role in dermatological diagnostics, particularly for conditions like PG, is likely to expand. Nonetheless, while dermatoscopy enhances and expedites diagnostic precision, it should be seen as part of a broader toolkit that includes clinical expertise and, when necessary, other invasive analytical techniques to ensure optimal patient care.