What could cause a swollen head of the penis and how is it treated?

Swollen Head of Penis: Causes and Treatment

Most Likely Diagnosis and Immediate Action

A swollen glans penis (head of penis) is most commonly caused by balanitis—inflammation of the glans—which can result from infectious agents (Candida species, bacteria including Staphylococcus and Streptococcus), contact dermatitis, or traumatic friction edema from sexual activity. 1, 2, 3

Differential Diagnosis by Clinical Context

Infectious Balanitis (Most Common)

• Candida albicans is the most frequently isolated organism in infectious balanitis, particularly in uncircumcised men 2
• Bacterial infections including Staphylococcus species and groups B and D Streptococci are common bacterial causes 2
• Clinical presentation typically includes erythema, swelling, and possible discharge, though the clinical appearance alone cannot reliably predict the causative organism 2, 4

Sexually Transmitted Infections

• In sexually active men under 35 years, consider Chlamydia trachomatis and Neisseria gonorrhoeae, which can cause urethritis with associated penile edema 5, 6
• Look for accompanying urethral discharge, dysuria, or urinary frequency 7
• Obtain urethral swab for Gram stain and nucleic acid amplification testing (NAAT) for N. gonorrhoeae and C. trachomatis 5

Traumatic/Mechanical Causes

• Penis friction edema presents as localized or total penile swelling following vigorous sexual activity, representing traumatic lymphatic drainage disruption 3
• This diagnosis is made by exclusion after ruling out infectious and obstructive causes 3
• Treatment consists of temporary abstinence from sexual intercourse for several weeks 3

Contact Dermatitis and Inflammatory Conditions

• Lichen planus, psoriasis, and contact dermatitis can cause inflammatory swelling of the glans 1
• Obtain thorough history regarding topically applied products (soaps, lubricants, condoms) 1

Critical Red Flags Requiring Emergency Evaluation

Life-Threatening Conditions to Rule Out

• Fournier's gangrene: Look for painful scrotal/perineal swelling with systemic signs (fever, tachycardia, sepsis), scrotal skin changes (crepitus, necrosis, rapidly spreading erythema) 5, 6, 8
• Risk factors include diabetes, immunosuppression, recent urogenital surgery, and obesity 5, 6
• Requires immediate broad-spectrum antibiotics and urgent surgical debridement 5, 8

Epididymitis with Extension

• Unilateral testicular pain and tenderness with palpable epididymal swelling may present with penile edema 5, 6, 7
• In men under 35 years: treat empirically with ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 10 days 5, 7
• In men over 35 years or with urinary tract abnormalities: use levofloxacin 500 mg orally once daily for 10 days OR ofloxacin 300 mg orally twice daily for 10 days 5

Diagnostic Algorithm

Initial Assessment

1. Determine if patient is circumcised: Balanitis occurs almost exclusively in uncircumcised men 2
2. Assess for systemic signs: Fever, rigors, rapidly progressive symptoms suggest necrotizing infection requiring emergency intervention 5, 6, 8
3. Sexual history: Recent sexual activity (friction edema vs. STI), number of partners, condom use 7, 1
4. Product exposure: Soaps, lubricants, topical medications 1

Laboratory and Imaging Studies

• For suspected infectious balanitis: Culture of glans and prepuce for bacteria and fungi 2
• For suspected STI-related edema: Urethral Gram stain, NAAT for N. gonorrhoeae and C. trachomatis on urethral swab or first-void urine 5
• Ultrasound with Doppler if testicular involvement suspected to assess for epididymitis, abscess, or testicular pathology 6

Treatment Approach

For Infectious Balanitis

• Candida balanitis: Topical antifungal agents (clotrimazole, miconazole) for 7-14 days 2
• Bacterial balanitis: Topical or systemic antibiotics based on culture results; empiric therapy with broad-spectrum coverage if severe 2
• Keep glans dry and ensure balanced genital hygiene 1

For STI-Associated Penile Edema

• Men under 35 years: Ceftriaxone 1 g IM or IV single dose PLUS azithromycin 1 g orally single dose for gonococcal infection 5
• For chlamydial infection: Doxycycline 100 mg orally twice daily for 7 days OR azithromycin 1.0-1.5 g orally single dose 5
• Treat sex partners if contact occurred within 60 days preceding symptom onset 5

For Friction Edema

• Temporary abstinence from sexual intercourse for several weeks until swelling resolves 3
• No specific medical therapy required 3

For Contact Dermatitis

• Identify and eliminate causative agent 1
• Topical corticosteroids for inflammatory component 1

Follow-Up and Reassessment

• Failure to improve within 3 days requires reevaluation of diagnosis and consideration of alternative etiologies including abscess, tumor, or resistant organisms 5, 6
• Persistent swelling after antimicrobial therapy completion warrants comprehensive evaluation including imaging and possible biopsy 5
• Recurrent balanitis: Consider therapeutic circumcision as definitive treatment 1

Common Pitfalls

• Assuming all penile swelling is infectious: Friction edema and contact dermatitis are common non-infectious causes that require different management 1, 3
• Missing Fournier's gangrene in early stages: Insidious onset with minimal external signs can mask extensive internal necrosis, particularly in obese or diabetic patients 5, 6, 8
• Relying solely on clinical appearance: The visual presentation of balanitis has little predictive value for identifying the causative organism—culture is essential 2
• Inadequate sexual partner treatment: Failure to treat partners leads to reinfection in STI-related cases 5