Differential Diagnosis for Rash Under Beard

• Single most likely diagnosis
  • Contact Dermatitis: This is the most likely diagnosis due to the common occurrence of irritant or allergic reactions to shaving creams, soaps, or other products used on the beard area, leading to a rash.
• Other Likely diagnoses
  • Folliculitis: An inflammation of the hair follicles, often caused by bacterial or fungal infections, which can be exacerbated by shaving or poor hygiene.
  • Pseudofolliculitis Barbae: A condition characterized by ingrown hairs, which can cause a rash-like appearance under the beard, especially in individuals with curly hair.
  • Seborrheic Dermatitis: A skin condition that can cause a rash, often in oily areas of the body, including under the beard, due to an overproduction of sebum.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cellulitis: A bacterial skin infection that can spread rapidly and become serious if not treated promptly. While less common, it's crucial to consider due to its potential severity.
  • Methicillin-Resistant Staphylococcus Aureus (MRSA): A type of bacterial infection that is resistant to many antibiotics and can cause severe skin infections, including under the beard.
• Rare diagnoses
  • Keratosis Pilaris: A condition that causes small, rough patches on the skin, which can occasionally appear under the beard, though it's more common on other parts of the body.
  • Sarcoidosis: A disease that can cause skin rashes, among other symptoms, and while rare, it should be considered in the differential diagnosis for a rash under the beard, especially if other systemic symptoms are present.