Differential Diagnosis for 47-year-old Female with Extreme Fatigue and Rash
- Single most likely diagnosis:
- Contact Dermatitis: Given the acute onset of a burning and itchy rash on the abdomen, contact dermatitis is a plausible diagnosis. This condition occurs when the skin comes into contact with an irritant or allergen, leading to an inflammatory response. The fact that the rash appeared on Monday suggests a potential exposure to a new substance or product.
- Other Likely diagnoses:
- Atopic Dermatitis (Eczema): Although the patient's autoimmune workup was negative, atopic dermatitis can present with itchy, burning rashes and is often associated with fatigue due to sleep disturbances.
- Urticaria: This condition is characterized by itchy, raised hives that can appear anywhere on the body, including the abdomen. Fatigue is not a primary symptom, but it can be secondary to discomfort and sleep disturbances.
- Drug Rash: Given that the patient has been evaluated multiple times, it's possible that a new medication or a change in medication dosage could be the culprit behind the rash.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Stevens-Johnson Syndrome (SJS) or Toxic Epidermal Necrolysis (TEN): These are life-threatening conditions usually triggered by medications or infections, characterized by widespread skin necrosis and detachment. Although rare, they require immediate recognition and treatment.
- Erythema Multiforme: This is an immune-mediated condition that can be triggered by infections or medications, presenting with target-like lesions. It can be a precursor to more severe conditions like SJS/TEN.
- Rare diagnoses:
- Pemphigus: A group of autoimmune diseases that result in blistering of the skin and mucous membranes. While rare, pemphigus can present with significant morbidity if not recognized and treated appropriately.
- Dermatomyositis: An inflammatory disease characterized by skin rash and muscle weakness. The rash can precede muscle symptoms, making it a consideration in patients with unexplained fatigue and rash.