Differential Diagnosis for Rash in Sacrum Spreading to Buttock, Scrotum, and Penis in Middle-Aged Male
- Single Most Likely Diagnosis
- Tinea Cruris (Jock Itch): A common fungal infection in the groin area, often spreading to the buttocks, scrotum, and penis, especially in middle-aged males who engage in activities that increase moisture and friction in these areas.
- Other Likely Diagnoses
- Contact Dermatitis: An allergic or irritant reaction to substances coming into contact with the skin, which could start in the sacrum area and spread due to continued exposure or autoinoculation.
- Seborrheic Dermatitis: Although more commonly associated with the scalp, face, and torso, seborrheic dermatitis can occasionally present in the genital area, causing a rash.
- Psoriasis: An autoimmune condition that can cause skin cells to build up and form scales and itchy, dry patches, potentially affecting the sacrum, buttocks, scrotum, and penis.
- Do Not Miss Diagnoses
- Herpes Simplex Virus (HSV): Although less common in this specific distribution, HSV can cause severe, painful lesions and has significant implications for sexual health and transmission.
- Syphilis (Secondary): Characterized by a rash that can appear anywhere on the body, including the palms and soles, and can involve the genital area, making it crucial not to miss due to its serious health and transmission implications.
- Rare Diagnoses
- Erythrasma: A bacterial infection more commonly found in the groin area, characterized by well-demarcated, brownish-red patches, which could be considered in the differential for a rash in these areas.
- Lichen Sclerosus: A rare condition that creates patchy, white skin that's thinner than normal, often affecting the genital and anal areas, which could be a consideration in this case due to the area affected.
- Fixed Drug Eruption: A condition where skin lesions appear at the same site each time a particular drug is taken, which could potentially affect the sacrum, buttocks, scrotum, and penis if the drug is taken regularly.