Differential Diagnosis for 28-year-old Male with Diaphoresis, Rashes, and Serpigenous Scars

Single Most Likely Diagnosis

• Pellagra: This condition is caused by a deficiency in niacin (vitamin B3) and is characterized by the three Ds: diarrhea, dermatitis, and dementia. The patient's symptoms of diaphoresis and rashes, particularly around the eyes, along with serpigenous scars, could be indicative of pellagra, especially considering the patient was initially on L-Carnitine and Creatine Monohydrate, which might not provide sufficient niacin.

Other Likely Diagnoses

• Niacin Deficiency: Similar to pellagra, a direct deficiency in niacin without the full spectrum of pellagra could cause skin symptoms and potentially the serpigenous scars due to poor wound healing.
• Contact Dermatitis: The rashes around the eyes could be due to an allergic reaction or irritant causing contact dermatitis, potentially from the supplements or other environmental factors.
• Atopic Dermatitis (Eczema): This chronic condition could explain the rashes and serpigenous scars, especially if the patient has a history of atopic diseases.

Do Not Miss Diagnoses

• Sarcoidosis: Although less common, sarcoidosis can cause skin lesions and rashes, and it's crucial not to miss this diagnosis due to its systemic implications and potential for serious complications.
• Lupus Erythematosus: This autoimmune disease can present with a variety of skin manifestations, including rashes and scars, and is critical not to overlook due to its potential for severe organ involvement.
• Vitamin B12 Deficiency: While less directly linked to the specific symptoms, a deficiency in vitamin B12 can cause a range of systemic issues, including neurological and dermatological problems, making it a diagnosis not to miss.

Rare Diagnoses

• Porphyria Cutanea Tarda: A disorder that can cause blistering skin lesions upon sun exposure, potentially leading to scarring. It's a rare condition but could explain some of the patient's symptoms.
• Ehlers-Danlos Syndrome: This group of disorders affects connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. While rare, it could potentially explain the serpigenous scars if associated with poor wound healing or skin hyperextensibility.