What is the likely diagnosis and recommended treatment for a 43-year-old male with penile itching and mild erythema after contact with a dirty toilet in prison, who is concerned about a sexually transmitted infection?

Likely Diagnosis and Management of Penile Pruritus with Mild Erythema

This patient most likely has irritant contact dermatitis from environmental exposure to the toilet surface, not a sexually transmitted infection, and should be treated with a mid-potency topical corticosteroid such as triamcinolone 0.1% cream twice daily for 7-14 days. 1

Clinical Reasoning

The presentation strongly argues against STI:

• Isolated pruritus with minimal erythema and no discharge, ulceration, or systemic symptoms does not fit the typical presentation of gonorrhea or chlamydia, which characteristically cause mucopurulent or purulent urethral discharge and dysuria 2
• The temporal relationship to toilet contact and absence of urethral symptoms makes irritant contact dermatitis the primary diagnosis 1, 3
• Contact dermatitis of the genital area commonly results from persistent moisture, maceration, and irritant exposure—exactly matching this patient's history of contact with a contaminated surface 4

Diagnostic Evaluation to Perform

Examine for urethral discharge by milking the urethra from base to meatus—if any discharge is present, obtain a Gram stain showing ≥5 polymorphonuclear leukocytes per oil immersion field to diagnose urethritis 2

If no discharge is present and the patient denies dysuria, STI testing is not indicated based on CDC guidelines, which reserve testing for patients with urethritis symptoms 5

However, given the prison setting and patient anxiety:

• Offer nucleic acid amplification testing (NAAT) for N. gonorrhoeae and C. trachomatis on first-void urine to provide definitive reassurance 2
• Offer syphilis serology and HIV testing as part of comprehensive screening in this high-risk population 5

First-Line Treatment

Prescribe triamcinolone 0.1% cream applied twice daily to affected areas for 7-14 days, as mid-potency topical corticosteroids successfully treat localized acute contact dermatitis 1

Instruct the patient to avoid potential irritants including harsh soaps, prolonged moisture, and tight-fitting underwear 4, 1

Recommend gentle cleansing with water only and thorough drying of the genital area 3

Critical Pitfall to Avoid

Do not empirically treat with antifungals—fungal balanitis typically presents with white plaques, satellite lesions, or thick scaling, none of which are described in this case 5, 4

Do not empirically treat for STI without evidence of urethritis—the CDC explicitly recommends against treating asymptomatic patients without documented infection, as this promotes antibiotic resistance and does not improve outcomes 5

Follow-Up Protocol

Reassess within 7 days—if pruritus and erythema have not improved, consider:

• Allergic contact dermatitis requiring patch testing to identify specific allergens 1, 3
• Lichen sclerosus, which presents as atrophic white patches and requires biopsy for confirmation 4
• Plasma cell balanitis or squamous cell carcinoma in situ, both requiring biopsy to exclude malignancy 4

If symptoms completely resolve with topical corticosteroids, this confirms the diagnosis of contact dermatitis and no further workup is needed 1

Patient Counseling

Reassure the patient that STIs are not transmitted through toilet seats—gonorrhea and chlamydia require direct mucosal contact with infected secretions 5

Explain that his symptoms are consistent with skin irritation from environmental contact, not infection 1, 3

If NAAT testing is performed, instruct him to return for results in 3-5 days and emphasize that treatment will only be given if tests are positive 2