Categorization of and comments on isomorphic and isotopic skin reactions

Mycobacterium tuberculosis found at both skin lesions and Mantoux testing site in a patient with erythema induratum of Bazin

“…The pathogenesis of Koebner reaction remains unclear 5, 6. It is believed to be associated with some inflammatory factors (e.g.…”

Isolated annular atrophic lichen planus of the mammary areola

“…The occurrence of AALP on the mammary areola in our case may be best explained by an isomorphic (Koebner) or isotopic phenomenon following a minor trauma that probably occurred during breastfeeding. It has been known that various forms of trauma, including not only penetration but also external mechanical stimuli such as stretching, excoriations, bites, burns, pressure, friction, allergic, and irritant reactions as well as sucking, can precipitate isomorphic or isotopic reactions in LP . We may speculate that the patient probably had an obscure form of LP in the past, such as the reticular form of the oral LP which is mostly an underdiagnosed health issue because of the asymptomatic nature of this subtype, and the mammary areola may have become a ‘locus minoris resistentiae’ to the isomorphic response of the preexisting disease.…”

Mucinous adenocarcinoma in association with hidradenitis suppurativa: a new example of isoscartopic response

“…A recent classification of isomorphic and isotopic skin reactions has proposed a newly coined terminology to indicate each specific cause responsible for the occurrence of an ICD . According to this new categorization, the case reported by Alkeraye et al .…”