its hallmark features include the presence of cutaneous 
 granulomatous lesions noncontiguous with the gastrointestinal tract or fistulae 
 .
we report a very rare case of metastatic crohn 's disease 
 affecting the ear in a man with longstanding crohn 's disease .
we aim to 
 highlight the need for clinical suspicion of systemic diseases that may present 
 as a localised ear lesion , in particular , the rare entity of metastatic crohn 's 
 disease .
a 43-year - old man with an 18 years history of crohn 's disease 
 developed a severe erythematous and exudative skin lesion in the right postauricular 
 cleft region .
the patient had recently completed a course of the 
 therapeutic drug infliximab , a monoclonal antibody for tumour necrosis factor 
 ( tnf ) , which is a key inflammatory agent in systemic inflammatory conditions . 

gastroenterologists were concerned that the skin lesion was an infective 
 complication of the new therapeutic regimen due to a possible immunosuppressive 
 action .
several antibacterial agents were used with no clinical benefit , and 
 the patient was then referred to the ent department for a second opinion . 
 concurrently , the patient had a recurrence of severe perineal crohn 's disease 
 and warranted further course of infliximab .
however , given the issue of 
 possible association with the skin lesion , the treatment decision was deferred 
 pending resolution of the skin condition .
initial ent examination excluded an otitis externa causing local 
 inflammation from overspill onto the adjacent skin area .
appearance of the skin 
 lesion was in keeping with either an infection or severe eczematous 
 inflammation .
a skin swab for culture was taken and triadcortyl ointment 
 applied . during the initial consultation , the patient complained of a similar 
 lesion starting in the umbilicus region .
the swab result reported heavy growths 
 of beta - hemolytic streptococcus and staphylococcus aureus with moderate anaerobes . 

triple therapy with flucloxacillin , erythromycin , and metronidazole proved to 
 be ineffective . during this period
, there was gradual deterioration of the 
 lesion , which prompted a biopsy of the periauricular skin lesion .
the 
 pathologist reported the biopsy to represent a chronic noncaseating 
 granulomatous lesion consistent with a diagnosis ofmetastatic crohn 's 
 disease ( please refer pathology report ) .
subsequently , with dermatology advice , treatment with high - dose 
 betnovate cream , oral steroids , and infliximab resulted in rapid remission of 
 the skin condition ( both the postaural and umbilical areas ) and the perineal 
 crohn 's disease .
histological haematoxylin 
 and eosin sections ( figure 1 ) demonstrated chronic inflammation of the dermis with 
 admixed epithelioid and giant cell granulomas .
furthermore , there was an absence of fungi , staining for acid and 
 alcohol fast bacilli were 
 negative , and birefringent foreign bodies were not seen .
metastatic cutaneous crohn 's disease refers to the presence of a 
 skin lesion containing epithelioid 
 and giant cell granulomas as seen in the affected bowel segments of patients with 
 crohn 's disease , but is physically separated from the gastrointestinal tract . 

this condition is distinct from other more well - characterized cutaneous 
 manifestations which include pyoderma gangrenosum , erythema nodosum , 
 polyarteritis nodosa , and epidermolysis acquisita .
although the estimated 
 incidence of cutaneous manifestation of crohn 's disease varies widely between 
 2% and 44% , 
 true metastatic cutaneous crohn 's disease is exceedingly rare .
metastatic crohn 's disease does not appear to have any distinct 
 relationship with the severity of the crohn 's bowel disease , and indeed may 
 even precede gastrointestinal involvement . 

however , there is a suggestion in the limited literature available that 
 there may be an association with perianal crohn 's disease . of the reported 
 cases of metastatic crohn 's disease involvement primarily of the lower limbs 
 and trunk regions with a predilection for skin fold areas and
there has been only one reported case of facial involvement documented more 
 than 30 years ago . to date ,
given the rarity of the condition , there is no 
 gold - standard therapy for metastatic crohn 's disease .
the use of systemic 
 and topical steroids , antibiotics , and immunosuppressive agents such as 
 azathioprine , sulfasalazine , and methotrexate has been described with variable success . the 
 use of infliximab , an antitumour necrosis factor monoclonal antibody , as one of 
 the latest treatment options has been described in a few case reports to be 
 more effective in maintaining disease remission , especially with repetitive 
 administration and when used concomitantly with other more mainstream therapies 
 [ 57 ] .
however , given their recent introduction 
 to clinical use , in addition to a better evidence for clinical efficacy in 
 various disorders , new side effects may also become apparent with time and 
 should be carefully evaluated . in the case
being presented , the possibility of an unusual 
 diagnosis for the skin lesion was raised by several features : the sudden onset 
 of postauricular rash in a gentleman with no previous ear or skin condition ; 
 the aggressive nature of the purulent rash ; the observed resistance to several 
 common treatments used including multiple antimicrobial agents and topical 
 steroid cream .
the diagnosis of the rare cutaneous crohn 's disease was first 
 suggested by the biopsy demonstrating chronic granulomatous inflammation in a 
 patient known to be suffering from active crohn 's disease .
biopsies 
 demonstrating chronic granulomatous inflammation of the skin require the 
 pathologists to consider other and more common disorders including sarcoidosis , 
 tuberculosis and fungal or parasitic infections , foreign body granulomas , and 
 annular elastocystic granuloma .
histological analysis failed to demonstrate any 
 of the pathognomonic features of the other granulomatous conditions .
the 
 diagnosis of metastatic crohn 's was further supported by the rapid remission 
 both of the skin rash and perineal crohn 's disease in response to treatment 
 with high - dose 
 local steroid cream , oral steroids , and concomitant infliximab infusion . despite its rarity ,
a meticulous evaluation including a thorough 
 history and examination , and biopsy in cases unresponsive to simple measures , 
 together with a high index of clinical suspicion in those with an established 
 diagnosis or presenting with concomitant clinical features of crohn 's disease , 
 may provide early diagnosis of this skin condition which can be disfiguring and 
 emotionally distressing to the patient .
the diagnosis of metastatic crohn 's 
 disease may be relatively easier in patients with established crohn 's disease 
 compared to those cases where the skin lesions precede bowel involvement . in 
 the latter cases , diagnosis by biopsy should then lead to appropriate 
 counseling about the diagnosis of crohn 's disease and the future onset of the 
 more significant bowel disease .
we hope by reporting this rare and interesting case that we may highlight the 
 need to consider systemic diseases , in particular , chronic inflammatory 
 conditions such as crohn 's disease , as causes of skin lesions of the ear and 
 face that are unresponsive to simple treatments .

 metastatic crohn 's disease is an uncommon cutaneous manifestation of crohn 's disease.metastatic crohn 's lesions have a predilection for the 
 skin fold , limbs , and trunk.metastatic 
 crohn 's involving ear is extremely rare.to date , there is no gold standard treatment for 
 metastatic crohn 's disease.treatment with 
 repetitive administration of infliximab together with other mainstream 
 therapies is promising in maintaining disease remission . 
 
metastatic crohn 's lesions have a predilection for the 
 skin fold , limbs , and trunk .
treatment with 
 repetitive administration of infliximab together with other mainstream 
 therapies is promising in maintaining disease remission .
 
 objective . we reported a very rare case of metastatic crohn 's disease involving the retro - auricular region . 
 method . a case report and a review of literature concerning metastatic crohn 's disease . 
 results . 
 metastatic crohn 's disease is an uncommon extraintestinal cutaneous manifestation of crohn 's disease and a very rare case involving the retro - auricular region is reported here . given the limited existing literature little is known about this condition . 
 the skin lesions appear to have a predilection for the lower trunk and genitalia regions . 
 there is no clear association with the severity of crohn 's disease and in some cases , the cutaneous lesions predate the onset of gastrointestinal crohn 's disease . 
 treatment with immune - modulating medications together with the antitumour necrosis factor monoclonal antibody therapy appears to offer the best chance of remission . conclusion . by reporting this interesting and rare condition 
 we also hope to highlight the importance of considering underlying chronic systemic disorders , such as crohn 's disease , when presented with skin lesions resistant to simple local treatments . 
1. Introduction
2. Case Report
3. Pathology Report
4. Discussion
5. Summary