acquired perforating collagenosis ( apc ) is known to be a really difficult disease to treat .
this fact complicates the development of an effective therapy . to date , several treatments have been used , including corticosteroids , retinoids , antihistamines , antibiotics , allopurinol and phototherapy , with variable success .
we describe a 65-year - old patient with long - standing type 2 diabetes mellitus who presented with a 2-year history of papular lesions about 34 mm in diameter , hyperkeratotic , very itchy and located primarily on the back ( fig .
the hematoxylin - eosin stain showed an ulcerative lesion with collagen fibers , keratinous material and lymphocytic infiltration .
the lower edge of the ulcer was interrupted by collagen fibers running perpendicular to it ( fig .
use of topical corticosteroids and antihistamines did not result in any improvement of the skin lesions .
the lesions were treated for 2 months with topical tacalcitol ( once daily ) and disappeared completely ( fig .
however , 4 weeks after finishing the treatment , the lesions recurred less severely , showing an early recovery after reintroduction of tacalcitol during 3 weeks .
now , the patient is treating himself when the lesions recur using the same treatment with full recovery between outbreaks .
perforating skin diseases are characterized by hyperkeratotic papular lesions where the connective tissue fibers are eliminated through the epidermis .
reactive perforating collagenosis usually appears during childhood , following a history of trauma to the skin .
elastosis perforans serpiginosa typically develops in children and young adults . in up to 40% of cases , it is related to genetic disorders ( ehlers - danlos syndrome , down syndrome , acrogeria and others ) .
both dermatoses share a hereditary basis , with a scarce prevalence in the general population .
apc tends to occur in adults , usually related to diseases with a long - term outcome such as chronic renal failure or diabetes mellitus and less frequently in chronic hepatopathy , hematologic malignancies and solid neoplasia .
finally , there is a wide variety of perforating dermatoses called secondary dermatosis , in which transepidermal elimination of connective tissue fibers occurs secondary to other basic dermatological conditions such as mycotic infections , granulomas or skin neoplasm [ 1 , 2 , 3 ] . an accurate etiopathogenesis of apc has not been determined .
patients with type 2 diabetes mellitus and chronic kidney failure , mainly those treated with hemodialysis , are known to develop microvascular diseases leading to intense pruritus .
repeated microtrauma caused by scratching may cause necrosis in the connective tissue fibers of the dermis , resulting in transepidermal elimination [ 4 , 5 ] .
moreover , these patients show epithelial cell hyperplasia , motivating an inflammatory foreign body reaction to altered collagen and elastin fibers .
levels of fibronectin are increased in the plasma and skin where perforating lesions appear in patients with diabetes and uremia .
fibronectin has been proven to have an influence on cell differentiation and migration . in the case of perforating dermatoses ,
fibronectin is associated with type iv collagen fibers and keratinocytes causing epithelial cell hyperplasia , therefore triggering an onset of perforating injuries . with regard to its treatment
, there is a clear correlation between the disappearance of pruritus and improvement of the lesion .
other alternative therapies have been tested , although experience is summarized in a small series of cases .
allopurinol has been used , regardless of plasma levels of uric acid , with good results .
its effectiveness seems to be related to its antioxidant effect , since it is capable of inhibiting xanthine oxidase , thus decreasing the production of oxygen free radicals that damage collagen fibers , and collagen fiber cross - linking itself .
narrowband ultraviolet b has also been used in the treatment of apc . apart from an antiproliferative and anti - inflammatory effect
, this therapy seems to relieve the pruritus , consequently improving lesions , although recurrence happens in a variable interval once narrowband ultraviolet b treatment is stopped . in some cases , antimicrobials such as rifampicin , clindamycin and doxycycline
this seems to prove that the presence of infectious agents may contribute to the development of apc [ 9 , 10 , 11 ] .
its main action mechanism is through the regulation of keratin , with a significant antiproliferative effect .
it is used primarily in the treatment of plaque psoriasis , although various cases have been published where treatment with tazarotene provides an improvement of the perforating collagenosis lesions . finally , tacalcitol is a vitamin d3 synthetic analogue used in the topical treatment of psoriasis .
this drug inhibits the proliferation of keratinocytes and , at the same time , modulates inflammatory mediators and the skin 's immune system .
no previous data has been published on the use of tacalcitol in perforating collagenosis . as mentioned above ,
, we decided to use this drug in the treatment of our patient , achieving excellent results .
 acquired perforating collagenosis ( apc ) is a rare perforating dermatosis characterized by transepidermal collagen elimination . 
 we describe a 65-year - old patient , with long - standing type 2 diabetes mellitus and a 2-year history of itchy hyperkeratotic nodules situated on the back , who was subsequently diagnosed with apc . 
 treatment included topical corticosteroids and antihistamines , without improvement of the lesions . 
 however , therapy with topical tacalcitol administered for 2 months produced a significant response leading to complete remission of apc . 
Introduction
Case Report
Discussion
Disclosure Statement