A crust that always returns to the same spot after being scratched, a small pearly bump on the wing of the nose that hasn’t healed for three months: it is often in these mundane situations that a skin carcinoma goes unnoticed. Identifying skin cancer from its visual appearance requires knowing exactly what to observe, in which area, and with what tool.
Dermatological photos do not replace a medical diagnosis, but they train the eye to spot what justifies a quick consultation.
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Non-healing lesion: the most underestimated warning sign
One naturally thinks of moles when talking about skin cancer. The basal cell carcinoma, although the most common, does not resemble a mole. It often appears as a small translucent papule, pink or pearly, sometimes crossed by fine vessels visible to the naked eye.
The most reliable sign remains a lesion that does not heal after four to six weeks. It may bleed slightly, form a crust, seem to heal, and then reappear. On fair skin, this lesion is quite distinguishable. On olive or dark skin, it sometimes takes on a pigmented brown or bluish appearance, complicating identification in photos.
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The squamous cell carcinoma, on the other hand, adopts a rougher appearance. One generally observes a scaly, red plaque, sometimes thickened, which may resemble a wart or persistent eczema. Unlike basal cell carcinoma, the squamous cell carcinoma can produce metastases if left untreated, making visual detection all the more useful.
To better understand the appearance of these lesions according to their stage, consulting photos of carcinoma and skin cancer helps calibrate one’s gaze before a dermatological appointment.
Dermoscopy and digital photo: when the image goes beyond simple illustration
Photos of skin cancers shared on medical sites primarily serve to raise awareness. In clinical practice, the photo goes further. Dermoscopy, a surface imaging technique that magnifies the lesion and eliminates reflections, allows for the observation of structures invisible to the naked eye: pigment network, globules, blue-white areas, arborizing vessels.
A notable finding from recent research: in certain analysis configurations, dermoscopy alone has proven to be more accurate than a stack of modalities for estimating the thickness of a basal cell carcinoma. In other words, a high-quality image, well-framed and well-lit, can provide more information than a poorly coordinated multi-signal assessment.
We are far from a photo taken with a smartphone in the bathroom. The quality of the image conditions the reliability of the interpretation. A dermatologist using digital dermoscopy can track the evolution of a lesion over time, compare images at regular intervals, and detect subtle changes in shape or color.
What the photo does not show
A photo, even a dermatoscopic one, does not replace the anatomical pathology examination. Only a biopsy confirms the exact nature of a lesion. Feedback varies on the ability of photos to distinguish a superficial carcinoma from a benign inflammatory lesion, especially in difficult areas like the scalp or ears.
AI tools and smartphone detection: what really exists in 2025-2026
Several devices incorporating artificial intelligence have received regulatory approvals for the evaluation of suspicious skin lesions. Two concrete examples deserve mention.
- DermaSensor, approved by the FDA in 2024, combines spectroscopy and AI for a non-invasive evaluation. It is a decision-support tool intended for healthcare professionals, not a public application.
- DERM Zero, developed by Skin Analytics, received a Class III CE marking in the European Union in 2026, the highest regulatory level for a medical device. It allows for autonomous clinical evaluation from photos taken with a smartphone.
These tools do not function like an Instagram filter. They analyze specific morphological characteristics (asymmetry, border, color, diameter, evolution) and compare them to massive databases of diagnosed lesions. Their reliability directly depends on the quality of the submitted photo: natural lighting, absence of blur, tight framing on the lesion.
ABCDE rule applied to photos: a practical self-monitoring guide
The ABCDE rule remains the reference tool for skin self-examination. When taking a photo of a suspicious lesion to show to a doctor, these five criteria structure the observation.
- Asymmetry: the two halves of the lesion do not match if mentally folded in half.
- Border: the edges are irregular, notched, or poorly defined.
- Color: multiple shades coexist (brown, black, red, white, blue) within the same lesion.
- Diameter: the size exceeds that of a pencil eraser, about 6 mm, although some melanomas are smaller.
- Evolution: the lesion changes in size, shape, color, or relief over the weeks.
For the photo to be usable, it is preferably taken in daylight, at a distance of 10 to 15 cm, with a reference object (coin, ruler) placed next to it to indicate scale. Two photos taken one month apart are better than a single image, as it is the evolution that alerts the dermatologist the most.
Basal cell carcinomas respond less well to the ABCDE grid, originally designed for melanoma. Their detection relies more on texture (pearly appearance, telangiectasias) and this famous non-healing criterion. Photographing a persistent lesion and dating it allows for objectifying this duration during the consultation.