Differential Diagnosis for Penile Itching and Erythema
- Single Most Likely Diagnosis
- Contact Dermatitis: This is often the most common cause of penile itching and erythema, resulting from an allergic reaction or irritation to soaps, condoms, or other products that come into contact with the penis. The reaction can cause redness, itching, and sometimes small blisters.
- Other Likely Diagnoses
- Candidiasis (Yeast Infection): Caused by Candida albicans, this fungal infection can lead to itching, redness, and a white discharge. It's more common in individuals with diabetes or those who are immunocompromised.
- Balanitis: An inflammation of the glans penis, often caused by poor hygiene, infections (bacterial, fungal, or viral), or an allergic reaction. Symptoms include redness, itching, and sometimes discharge.
- Genital Herpes: A viral infection that can cause itching, burning, and small, painful blisters on the penis.
- Scabies: A parasitic infection caused by the mite Sarcoptes scabiei, leading to severe itching and a pimple-like skin rash.
- Do Not Miss Diagnoses
- Squamous Cell Carcinoma: Although rare, penile cancer can present with itching and erythema. It's crucial to rule out this diagnosis, especially in older men or those with a history of HPV infection.
- Lichen Sclerosus: A chronic inflammatory skin condition that can cause itching, pain, and scarring on the penis. If left untreated, it can increase the risk of penile cancer.
- Syphilis: A bacterial infection that can cause a variety of symptoms, including a painless sore (chancre) on the penis, which can be accompanied by itching and erythema in some cases.
- Rare Diagnoses
- Psoriasis: An autoimmune condition that can cause red, scaly patches on the penis, leading to itching and discomfort.
- Lichen Planus: A rare inflammatory condition that can affect the skin and mucous membranes, causing itching, redness, and sometimes blisters on the penis.
- Erythroplasia of Queyrat: A rare precancerous condition that appears as a red, velvety plaque on the penis, often accompanied by itching and burning.