Clinical photograph of a characteristic vesiculopustular skin lesion associated with disseminated gonococcal infection (DGI). The primary lesion is a solitary, erythematous papule, approximately 3-5 mm in diameter, with a centralized greyish-white pustule/vesicle and a dusky, necrotic appearance at the core. The surrounding skin shows generalized solar lentigines (freckling) but no acute inflammatory changes. This visual finding is a hallmark of the arthritis-dermatitis syndrome seen in Neisseria gonorrhoeae dissemination, typically presenting as sparse, painless, non-pruritic lesions on distal extremities. This image serves as an educational reference for identifying cutaneous manifestations of systemic sexually transmitted infections in a clinical setting.

Two-panel clinical photograph displaying primary skin lesions on the mid-right back, characteristic of pityriasis rosea. Panel A shows a 2.5-cm, well-demarcated, annular red plaque on the torso, along with a secondary, smaller, ill-defined erythematous papule located superiorly. Panel B provides a high-detail close-up of the primary plaque, illustrating its morphology: it features a raised, erythematous border and a slightly depressed center with fine, surface scaling. A focal hyperpigmented macule is visible within the center of the lesion, marking the site of a prior punch biopsy. These visual findings—specifically the larger herald-style plaque with centrifugal scaling—are key clinical indicators of spongiotic dermatitis and help differentiate it from other papulosquamous disorders such as tinea corporis or nummular eczema.

This clinical photograph displays skin lesions on the arm of a 21-day-old neonate, characteristic of the healing phase of varicella-zoster virus (VZV) infection. The primary finding is a centrally located, oval, crusted lesion showing a thick, dark-reddish-brown scab, indicating a dried vesicle or pustule. A second, smaller, and flatter brownish papule is visible proximally. The surrounding skin exhibits 'cutis marmorata,' a reticulated or mottled vascular pattern commonly seen in neonates due to vasomotor instability, but also noted here in the clinical context of neonatal varicella. No significant surrounding erythema or edema is observed at this stage of the lesions. This image serves as a pedagogical example of neonatal dermatology and the clinical progression of viral exanthems from vesicular to crusted stages. The presence of blue medical gloves indicates a clinical examination setting.

A clinical comparison chart and diagnostic visualization illustrating the progression of mpox (MPXV) skin lesions. The top row features seven photographic images (a-g) documenting the dermatological evolution: an early-stage vesicle (a), a small pustule (b), an umbilicated pustule with a central depression (c), a papule with central necrosis (d), an ulcerated lesion on a hand (e), multiple ulcerated lesions in a pubic region (f), and late-stage crusted plaques (g). The lesions exhibit characteristic features of orthopoxvirus infection, including perilesional erythema and central umbilication. The bottom row displays a corresponding SHAP (SHapley Additive exPlanations) analysis overlaid on each image. Positive SHAP values (indicated in red/purple) represent discriminative regions—specifically the primary lesions and surrounding inflammatory areas—used by a convolutional neural network (CNN) for diagnostic classification. Negative SHAP values (in blue) highlight healthy skin areas that detract from the viral prediction. This image serves as a clinical reference for disease staging and AI-assisted diagnostic transparency in infectious disease management.

A comparison chart illustrating the classification of pigmented skin lesions through schematic representations and clinical dermoscopic photographs. The figure is organized into six pairs (A-F), demonstrating a progression of morphological irregularity. On the left of each pair, a gray schematic diagram represents the lesion's lacunarity and geometric properties; on the right, a corresponding clinical dermoscopic image shows real-world examples. The progression moves from (A) 'No irregularity'—a smooth oval with homogenous pigmentation—to (B) simple internal asymmetry, (C) hierarchical internal asymmetry with multiple colored internal regions, and (D-F) increasing boundary asymmetry with lobulated borders and complex internal architectural patterns. Key dermoscopic features visible in the clinical images include reticular networks, globules, and varied pigmentation ranging from light tan to dark brown and reddish-purple. The figure serves as a diagnostic educational tool for identifying risk factors in melanocytic lesions, highlighting how mathematical lacunarity values correlate with increasing clinical and structural complexity.

This clinical dermatological comparison chart showcases visual differentiation between types of skin lesions as used in machine learning classification models. The upper section features a 'Clinical Photograph' of a melanocytic nevus (the primary case), appearing as a dark brown, well-circumscribed, oval macule with uniform pigmentation and smooth texture. It is positioned adjacent to a 'Counter example image' of a dermatofibroma, which displays a lighter, reddish-brown hue, less distinct borders, and a subtle central firm or dimpled texture characteristic of this benign fibrous tumor. The lower section presents four 'Prototype images' (exemplars) of melanocytic nevi, demonstrating natural variability in lesion morphology. These variations include differences in color intensity (ranging from tan to deep brown), border regularity, and the visibility of surrounding skin markings such as fine lines and hair follicles. This visual tool is designed for medical education and AI model interpretability, helping to distinguish between benign melanocytic proliferations and non-melanocytic skin lesions like dermatofibromas based on morphology, color distribution, and border characteristics.

This composite educational image illustrates macroscopic findings and schematic representations of secondary neoplasms arising on reconstructive flap skin paddles in the oral cavity. Panels A and B present a clinical photograph and corresponding diagram of a flap neoplasm located centrally on the skin paddle. The lesion is characterized by focal erythema and a protruding, partially elevated morphology. Panels C and D show a clinical photograph and diagram of a similar lesion that demonstrates erythema and partial elevation extending toward the skin-mucosa junction, representing a peripheral or junctional presentation. These images demonstrate the typical macroscopic features of 'flap cancers,' which in these clinical cases were histologically confirmed as well-differentiated squamous cell carcinomas. The visual focus is on the distinguishing features of secondary primary neoplasms arising in surgical flaps, highlighting the importance of monitoring skin paddles for new lesions such as erythema, papillary projections, or non-ulcerative protrusions.