Dermatoses with "collarette of skin"

• Published in: Indian journal of dermatology, venereology, and leprology Vol. 85; no. 1; pp. 116 - 124
• Main Authors: Adya, Keshavmurthy, Inamadar, Arun, Palit, Aparna
• Format: Journal Article
• Language: English
• Published: India Wolters Kluwer India Pvt. Ltd 01-01-2019; Medknow Publications and Media Pvt. Ltd; Scientific Scholar
• Subjects: Bacterial infections; Congenital diseases; Infections; Keratin; Microscopy; Skin diseases; Syphilis
• ISSN: 0378-6323; 0973-3922; 1998-3611
• DOI: 10.4103/ijdvl.IJDVL_623_17

Dermoscopically, the collarette appears as a continuous white ring of scales encircling a central erythematous papule with a surrounding rim of erythema [Figure 6]b.[20],[21],[22]{Figure 6} Bacillary angiomatosis Bacillary angiomatosis is primarily a vasoproliferative disease, seen in human immunodeficiency virus infected patients (with a CD4+ cell count of <50 mm−3) caused by Bartonella henselae and Bartonella quintana. [29],[30],[31] Pitted keratolysis Pitted keratolysis is a superficial bacterial infection caused by a variety of organisms (Kytococcus sedentarius, Dermatophilus congolensis, Actinomyces and Corynebacterium spp.) that commonly affects the weight-bearing areas of soles in hot and humid climates. [45],[46],[47] Gyrate Erythemas Erythema annulare centrifugum Erythema annulare centrifugum is a reactive migratory erythema that has been speculated to be associated with certain infections (Epstein-Barr virus infection, herpes zoster, molluscum contagiosum, candidiasis, dermatophyte infections, etc.), drugs (piroxicam, hydroxychloroquine sulfate, hydrochlorothiazide, amitriptyline, etc.) and certain other disorders such as sarcoidosis, hepatic and thyroid disorders, hematological and solid organ malignancies. Acral fibrokeratoma clinically resembles various other cutaneous tumors such as eccrine poroma, pyogenic granuloma [Figure 10], a rudimentary supernumerary digit [Figure 12], viral wart [Figure 7], dermatofibroma and a cutaneous horn [Figure 13]. [...]histopathological analysis is required for definitive diagnosis which shows a central area of increased vertically oriented collagen fibers with interspersed blood vessels underlying a hyperkeratotic and acanthotic epidermis with wide, elongated, branching rete ridges.