Dermoscopy of Infectious Dermatoses (Infectiouscopy) in Skin of Color - A Systematic Review by the International Dermoscopy Society "Imaging in Skin of Color" Task Force

Abstract

Dermoscopy has been showed to facilitate the non-invasive recognition of several infectious disorders (infectiouscopy) thanks to the detection of peculiar clues. Although most of the knowledge on this topic comes from studies involving light-skinned patients, there is growing evidence about its use also in dark phototypes. This systematic literature review summarizes published data on dermoscopy of parasitic, bacterial, viral and fungal dermatoses (dermoscopic findings, used setting, pathological correlation, and level of evidence of studies) and provides a homogeneous terminology of reported dermoscopic features according to a standardized methodology. A total of 66 papers addressing 41 different dermatoses (14 bacterial, 5 viral, 11 fungal infections, and 11 parasitoses/bites and stings) and involving a total of 1096 instances were included in the analysis. The majority of them displayed a level of evidence of V (44 single case reports and 21 case series), with only 1 study showing a level of evidence of IV (case-control analysis). Moreover, our analysis also highlighted a high variability in the terminology used in the retrieved studies. Thus, although promising, further studies designed according to a systematic and standardized approach are needed for better characterization of dermoscopy of infectious skin infections.

Figure 1

PRISMA flowchart displaying the selection process for study inclusion in the systematic review.

Figure 2

Examples of dermoscopic clues of bacterial diseases in dark-skinned patients: White structureless areas and reduction of eccrine gland openings in borderline tuberculoid leprosy (Courtesy of Matilde Krisha Montenegro, MD and Katherine Joy Sayo, MD – Manila, Philippines) (A); Yellow structureless areas along with white structureless areas, faint peripheral linear vessels with branches (arrow), and reduction of skin appendages (hairs/eccrine glands openings) in borderline lepromatous leprosy (B); Loss of pigment network along with white areas and reduction of eccrine glands openings and hair follicles in lepromatous leprosy (C); Reduction of skin appendages, erythema, white scales and follicular plugs in Type-1 lepromatous reaction (D); Homogenous white-pink area and brown-gray dots in Type-2 lepromatous reaction (Courtesy of Matilde Krisha Montenegro, MD and Katherine Joy Sayo, MD – Manila, Philippines) (E); Elongated linear vessels with branches and multiple white structureless areas in histoid leprosy (F).

Figure 3

Examples of dermoscopic clues of bacterial diseases in dark-skinned patients: Ill-defined white structureless area and reduction of skin appendages in hypopigmented leprosy (A); Follicular plugs with perifollicular white color in lichen scrofulosorum (B); Orange-yellow and bright white globules/structureless areas along with diffuse white scaling in lupus vulgaris (C); Peripheral white collarette scaling in palmar secondary syphilis (D); Yellow concretions around the hair shafts in trichomycosis axillaris (E); Multiple white globules (papillae) centered by dotted vessels in tuberculosis verrucosa cutis (F).

Figure 4

Examples of dermoscopic clues of viral diseases in dark-skinned patients: Multiple yellow-white globules and peripheral linear vessels with branches in molluscum contagiosum (A); Central pore surrounded by white globules/dots along with peripheral dotted vessels in molluscum contagiosum (B); Brown dots and dotted vessels over a white background in a plane wart (C); Brown structureless area (diffuse) and few dotted vessels in plane warts (D); Interruption of skin markings, dotted vessels and diffuse brown pigmentation in a common wart (E); Multiple grey papillae in a genital wart (F).

Figure 5

Examples of dermoscopic clues of fungal diseases in dark-skinned patients: White and yellow scaling/crusting, dotted vessels and purple (hemorrhagic) dots/globules along with yellow structureless areas and brown dots (better visible in the inset) in chromoblastomycosis (A); White scales, yellow and white structureless areas, and black grains (dots) (arrow) in mycetoma (B); Perifollicular white color along with white scales in the skin furrows in hypopigmented pityriasis versicolor (C); Folliculocentric pale papule in Pityrosporum folliculitis (D); Focal orange and white structureless areas and white scales in rhinofacial entomophthoromycosis (E); Follicular plugs and unfocused linear vessels over an orange-erythematous background in sporotrichosis (adapted from Dermoscopy in General Dermatology for Skin of Color, Errichetti E, Lallas A, eds. CRC Press 2021) (F); White peripheral collarette scaling with a jagged mixed (outer and inner) free edge in tinea corporis (G); Follicular pustules, perifollicular scaling/crusting and dystrophic broken hairs in tinea incognito (H); White scales in the skin furrows in tinea manuum (I).

Figure 6

Examples of dermoscopic clues of skin bites/stings and parasitoses in dark-skinned patients: purple dots and crusting in bedbug bites (A); Brown structureless areas and lines (in the skin furrows) in cydnidae pigmentation (B); Well-defined, segmented brown/white linear structures in cutaneous larva migrans (C); Multiple follicular plugs in cutaneous leishmaniasis (D); Empty nits (translucent elongated structures with flat ending) and head lice in pediculosis capitis (E); Crab-shaped pubic lice with thick claws grasping hair shaft in pediculosis pubis (F); Central crusting with peripheral brown structureless area surrounded by a white halo in tick bite (G); Central pore with a faint pigmented peripheral ring and peripheral white structureless area containing blue globules in tungiasis (Courtesy of Elizabeth Leocadia Fernandes, MD – Mogi das Cruzes, Brazil) (H); Myasis larva (I).