Differential Diagnosis for 3 Foci of Inflammation along the Skin of the Scrotum

Single Most Likely Diagnosis

• Folliculitis: This is a common condition characterized by inflammation of the hair follicles, often due to bacterial infection. The presence of multiple foci of inflammation along the scrotum could be consistent with folliculitis, especially if the patient has not been practicing good hygiene or has been shaving the area, which can introduce bacteria into the follicles.

Other Likely Diagnoses

• Contact Dermatitis: This condition occurs when the skin comes into contact with an irritant or allergen, leading to inflammation. Given the scrotal location, potential irritants could include soaps, detergents, or fabrics. The pattern of inflammation could suggest an allergic or irritant reaction.
• Eczema (Atopic Dermatitis): Eczema can manifest as inflamed, itchy patches on the skin and can occur on the scrotum. If the patient has a history of atopic diseases (asthma, allergies), this could be a more likely diagnosis.
• Seborrheic Dermatitis: Although more common on the scalp, face, and torso, seborrheic dermatitis can occasionally affect the genital area, including the scrotum, causing inflammation and flaky skin.

Do Not Miss Diagnoses

• Cellulitis: While the question mentions no evidence of abscess, cellulitis (a bacterial skin infection) can present with areas of inflammation and should be considered, especially if the patient is febrile or has other signs of infection. It's crucial to monitor for signs of spreading infection.
• Sexually Transmitted Infections (STIs): Certain STIs, such as herpes simplex virus (HSV) or syphilis, can cause skin lesions or inflammation in the genital area. Given the potential for serious consequences if left untreated, considering STIs is critical.

Rare Diagnoses

• Keratosis Pilaris: This condition causes small, rough patches on the skin and can occasionally appear on the genital area, though it's more common on the arms, legs, and buttocks.
• Lichen Planus: An inflammatory condition that can affect the skin and mucous membranes, lichen planus can cause purplish, itchy, flat bumps. It's less common but should be considered if other diagnoses are ruled out.
• Zinc Deficiency: Though rare, zinc deficiency can lead to skin lesions and inflammation, including in the genital area. This would be considered if the patient has a history of malnutrition or malabsorption.