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ausdoc . com . au 6 DECEMBER 2024
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SPOT DIAGNOSIS
Professor Dédée Murrell Head of dermatology , St George Hospital ; professor , faculty of medicine , University of NSW ; and honorary professorial fellow , The George Institute for Global Health , Sydney . Co-author : Dr Madeleine Stark , dermatology honorary medical officer in training , St George Hospital , Sydney , and dermatology clinical research fellow , Premier Dermatology clinical trials , Sydney .
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Round , red and itching all over
A 68-year-old Caucasian woman presents with a two-year history of an erythematous and intensely pruritic rash that she thinks is psoriasis . She first noted the rash on her feet and lower legs , and it has since spread to her groin , abdomen and arms . She had scalp psoriasis in early adulthood which responded to tar-based shampoos . She has not needed any further treatment for this for around 40 years . Believing this new presentation to be recurrence of psoriasis , she treated the rash with Advantan or Daviobet cream twice daily for two years . These controlled the pruritus initially , but the rash gradually spread and became more painful and pruritic . This is now limiting her activities of daily living and disrupting sleep . On examination , there are scattered erythematous annular patches on her groin , lower legs and arms . There is marked erythema of the pubic region extending to the upper thighs , with an arcuate spreading border . There is an approximately 7cm well demarcated heterogeneously erythematous annular plaque on her abdomen , with raised and erythematous borders , which demonstrates central clearing with post-inflammatory hyperpigmentation .
back down into the scrotum . In contrast , cryptorchid ( undescended ) or ectopic testes cannot be manipulated manually into the scrotal sac .
In adults with an impalpable testis , it is essential to examine the patient standing and supine , and to allow for adequate cremasteric relaxation to aid diagnostic differentiation .
The vast majority of cryptorchid testes are identified and treated in childhood . Adults with newly diagnosed cryptorchidism warrant consideration for specialist referral ; in males younger than 50 at diagnosis , surgical excision may be warranted to reduce testicular cancer risk . 1
Ultrasound is typically used to assess a retractile testis and surrounding structures and vasculature . The testis may be difficult to locate sonographically if it lies high in the scrotum or within the inguinal canal . However , ultrasound is of limited utility in cases of cryptorchidism , where the testis is intra-abdominal or pelvic in location . MRI is the imaging modality of choice in this situation . 3
In most cases of retractile testis , the initial approach is observation and monitoring of the movement of the testicle over time to see if it settles into the scrotum spontaneously . The patient may simply be able to manipulate the testicle back into the scrotum when it does retract .
However , adult cases associated with clinical features may warrant urology review . Historically , ilioinguinal nerve excision and botulinum toxin injections to the cremaster muscle have been the procedural interventions of choice . Ilioinguinal nerve excision involves surgically removing a portion of the ilioinguinal nerve to interrupt the cremasteric reflex and prevent the testicle from retracting .
Botulinum toxin injections to the cremaster muscle involve injecting a small amount of botulinum toxin into the muscle . This causes temporary paralysis , reducing the muscle ’ s ability to contract and causing the testicle to remain in a more stable position . 3
Orchidopexy is now a more commonly used treatment option for retractile testes . It allows
The vast majority of cryptorchid testes are identified and treated in childhood . Adults with newly diagnosed cryptorchidism warrant consideration for specialist referral .
for repositioning the testicle while minimising the risk of damage to other structures ; reduces the risk of complications from persistent retraction , such as testicular torsion ; is effective and durable ; and is an option for both children and adults .
Microsurgical and subinguinal cremaster muscle release may also be an option for those with chronic orchialgia that has clearly been identified to be secondary to a hyperactive cremaster muscle reflex . 4 , 5
Outcome
Eric is referred to a urologist and opts for cremasteric muscle release . After surgical recovery he is pleased with the outcome .
References on request from kate . kelso @ adg . com . au
In most cases of retractile testis , observant management is appropriate .
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What is the most likely diagnosis ?
a Discoid eczema b Tinea incognito c Plaque psoriasis d Discoid lupus erythematosus
ANSWER The answer is b . Tinea incognito describes fungal skin infection , the appearance of which has been altered by immunosuppressive therapies . This may be due to pre-existing immunosuppressive medications prescribed for other conditions ; or the rash may have been misidentified and incorrectly treated with topical steroids or other immunosuppressive agents , as in this case . These treatments change the appearance of the rash and may efface some of the more characteristic features of fungal infection . Compared with untreated tinea corporis , tinea incognito tends to be more extensive , erythematous , pruritic and pustular and may also lack the scale and raised borders that characterise untreated tinea corporis . 1 , 2
As with other fungal skin infections , this condition can affect patients of any demographic . Increasing access to overthe-counter topical steroid creams may increase the prevalence of this condition . Tinea incognito warrants consideration when there is a history of a rash that initially responded to treatment but relapses with withdrawal of treatment . Clinically , the appearance of tinea incognito can vary greatly and may mimic various skin conditions , including systemic lupus erythematosus , eczema , contact dermatitis , psoriasis , seborrheic dermatitis and erythema migrans . 3 Tinea infection can be diagnosed with fungal microscopy and culture and testing should generally be performed prior to commencing treatment to identify the pathogen and confirm the diagnosis . The lack of scale can complicate the collection of fungal scrapings .
Any topical immunosuppressants should be discontinued if feasible . The infection itself should first be treated with standard antifungal therapy , although systemic treatment may be required . In this case , the patient was advised to stop applying the topical immunosuppressant therapies and was prescribed topical terbinafine 1 % twice daily . In addition , she was prescribed oral terbinafine 250mg once daily after her FBC , EUC and LFT were reviewed and no contraindications to oral antifungal therapy was found . Considering the extensive nature of the fungal rash , a glucose tolerance test was also performed , which was normal .
References on request from kate . kelso @ adg . com . au