I have a hair‑like bump on my penis; what is it likely to be and how should it be managed?

Hair-Like Bump on Penis: Diagnosis and Management

The most likely diagnosis is an ingrown hair (pseudofolliculitis), which presents as a firm, well-circumscribed bump at a hair follicle site and should be managed conservatively with warm compresses, proper hair removal technique modification, and topical antibiotics if infected.

Most Likely Diagnosis: Ingrown Hair (Pseudofolliculitis)

Pseudofolliculitis occurs when curved hairs re-enter the skin after shaving or trimming, creating inflammatory papules or pustules that can appear as "bumps" at hair follicle sites 1, 2. The condition is particularly common in areas with coarse, curly hair and is precipitated by improper shaving techniques through both transfollicular (hair curves back into follicle) and extrafollicular (hair penetrates adjacent skin) mechanisms 1, 2.

Key Clinical Features to Confirm Diagnosis:

• Location: Penile shaft skin where hair follicles are present 3
• Appearance: Firm, well-circumscribed papule or pustule at a hair follicle 2
• Symptoms: May be tender if inflamed; typically non-tender if not infected 2
• History: Recent shaving, trimming, or hair removal 1, 2

Important Differential Diagnoses to Exclude

When to Suspect Something More Serious:

Genital warts (condylomata acuminata) should be considered if the lesion is:

• Exophytic, flesh-colored, cauliflower-like in appearance 3
• Multiple lesions that have progressively increased over months 3
• Associated with history of HPV exposure or multiple sexual partners 3

Epidermoid or sebaceous cyst presents as:

• A well-circumscribed, firm, mobile subcutaneous nodule 4, 5
• Non-tender unless infected 4, 5
• May contain keratin material and can grow slowly over months 5
• Requires surgical excision for definitive treatment 4, 5

Lichen sclerosus appears as:

• Porcelain-white atrophic patches, not as discrete bumps 6, 7
• Typically affects glans and prepuce, causing phimosis and scarring 6, 7
• Would not present as a single "hair-like bump" 6

Red Flags Requiring Biopsy:

Biopsy is mandatory if the lesion shows 6, 3:

• Pigmentation
• Induration or fixation to underlying tissue
• Ulceration or persistent erosion
• Persistent hyperkeratosis
• Failure to resolve with conservative management

Management Algorithm

Step 1: Conservative Management for Presumed Ingrown Hair

Immediate measures:

• Apply warm compresses 3-4 times daily to promote drainage 2
• Avoid further shaving or hair removal in the affected area 1, 2
• If pustular or showing signs of infection, apply topical antibiotic ointment 2

Modify hair removal practices 2:

• Use electric clippers instead of razors (leave 1-2mm stubble)
• If shaving is necessary, use single-blade razors with the grain
• Apply warm compresses before shaving to soften hair
• Avoid stretching skin during shaving

Step 2: Follow-Up Assessment at 1-2 Weeks

If resolved: Counsel on proper hair removal techniques to prevent recurrence 1, 2

If persistent but improving: Continue conservative measures for another 1-2 weeks 2

If worsening, enlarging, or not improving: Proceed to Step 3

Step 3: Reassess Diagnosis and Consider Alternative Etiologies

Examine for features of:

• Cystic lesion (epidermoid/sebaceous cyst): firm, mobile, well-circumscribed → refer for surgical excision 4, 5
• Genital warts: exophytic, cauliflower-like → treat with topical agents or refer to dermatology 3
• Atypical features (pigmentation, induration, ulceration) → biopsy mandatory 6, 3

Common Pitfalls to Avoid

Do not assume all penile bumps are benign without proper examination 3. While ingrown hairs are common, failure to recognize genital warts, cysts requiring excision, or premalignant lesions can lead to delayed diagnosis 6, 3.

Do not perform aggressive manipulation or attempt self-extraction, as this can worsen inflammation, cause scarring, and increase risk of secondary infection 1, 2.

Do not continue the same hair removal technique that precipitated the problem 1, 2. Patients must modify their grooming practices or pseudofolliculitis will recur 2.

Do not delay biopsy if the lesion is pigmented, indurated, ulcerated, or fails to resolve with conservative management, as these features raise concern for penile intraepithelial neoplasia or squamous cell carcinoma 6, 3.

When to Refer

Immediate referral to urology or dermatology if 6, 3, 7:

• Suspicion of malignancy (pigmented, indurated, ulcerated, fixed lesion)
• Rapidly enlarging mass
• Associated systemic symptoms (fever, severe pain)
• Cystic lesion requiring surgical excision

Routine referral if 2, 5:

• Persistent lesion after 4 weeks of conservative management
• Recurrent pseudofolliculitis despite modification of hair removal practices (consider laser hair removal)
• Patient desires definitive treatment for cosmetic or functional concerns