Differential Diagnosis for 75-year-old with Rash
- Single most likely diagnosis
- Intertrigo: Given the patient's age and the location of the rash (top of arm, abdomen, and under the breasts), intertrigo is a likely diagnosis. Intertrigo is a type of skin inflammation caused by friction and moisture, which can be exacerbated by warm weather, obesity, or diabetes. The fact that she had nystatin for yeast under her breasts suggests a history of fungal infections, which can also contribute to intertrigo.
- Other Likely diagnoses
- Contact dermatitis: This could be due to an allergic reaction or irritation from clothing, soaps, or other substances that come into contact with the skin.
- Seborrheic dermatitis: A common skin condition that can cause a rash, especially in older adults, often in areas with a high concentration of sebaceous glands.
- Tinea corporis (ringworm): A fungal infection that can cause a rash on various parts of the body, including the arms and abdomen.
- 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 life-threatening if not treated promptly. While less likely given the initial presentation, it's crucial to consider, especially in older adults with potentially compromised immune systems.
- Herpes zoster (shingles): Although the description doesn't strongly suggest shingles, missing this diagnosis could lead to serious complications, including postherpetic neuralgia.
- Rare diagnoses
- Pemphigus: A group of rare skin disorders that cause blistering of the skin and mucous membranes. It's less likely but should be considered if the rash does not respond to typical treatments.
- Bullous pemphigoid: Another rare autoimmune skin disease characterized by the formation of blisters. It's more common in older adults but still relatively rare compared to other skin conditions.