What are the diagnostic and management requirements for a 77-year-old female tumor patient with suspected bullous pemphigoid (BP) lesions and fever, without biopsy or direct immunofluorescence (DIF) confirmation?

Differential Diagnosis for a 77-year-old Female with Dissiminated Infected Bullous Pemphigoid Lesions

Single Most Likely Diagnosis

• Bullous Pemphigoid: Given the description of dissiminated infected bullous pemphigoid lesions, this is the most likely diagnosis. Bullous pemphigoid is an autoimmune disease characterized by the formation of bullae (blisters) on the skin, which can become infected. The patient's age and the presence of a tumor could potentially trigger or exacerbate the condition.

Other Likely Diagnoses

• Pemphigus Vulgaris: Another autoimmune disease that causes blistering of the skin and mucous membranes. It could be considered if the clinical presentation overlaps with bullous pemphigoid, especially in the absence of confirmatory tests.
• Staphylococcal Scalded Skin Syndrome (SSSS): Caused by staphylococcal toxins, SSSS can present with widespread skin lesions and fever, mimicking infected bullous pemphigoid.
• Toxic Epidermal Necrolysis (TEN): A severe skin condition usually triggered by medications, characterized by widespread skin necrosis and detachment. The presence of fever and widespread lesions could suggest TEN, especially if the patient has recently started new medications.

Do Not Miss Diagnoses

• Severe Cutaneous Adverse Reactions (SCARs): Including conditions like Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) and Stevens-Johnson Syndrome, these are potentially life-threatening and require immediate identification and treatment.
• Infectious Causes: Such as Ecthyma Gangrenosum in the context of Pseudomonas sepsis, or other bacterial infections that could mimic or complicate bullous pemphigoid, especially in an immunocompromised patient.
• Paraneoplastic Pemphigus: A rare autoimmune disorder associated with underlying neoplasms, which could be considered given the patient's history of a tumor.

Rare Diagnoses

• Epidermolysis Bullosa Acquisita (EBA): A rare autoimmune disease characterized by blistering of the skin, which could be considered if other diagnoses are ruled out.
• Linear IgA Bullous Dermatosis: An autoimmune condition that presents with blistering skin lesions, which could be a differential diagnosis if the clinical presentation and immunopathological findings align.

Requirements for Investigations or Procedures

• Biopsy and Direct Immunofluorescence (DIF): Essential for confirming the diagnosis of bullous pemphigoid and distinguishing it from other blistering diseases.
• Blood Cultures and Sensitivity Testing: To identify any underlying infections, especially given the patient's feverish state.
• Complete Blood Count (CBC) and Electrolyte Panel: To assess the patient's overall condition and potential for sepsis or electrolyte imbalances.
• Medication Review: To identify any potential culprits for drug reactions.

Best Plan for Management and Treatment

1. Infection Control: Manage any identified infections with appropriate antibiotics.
2. Wound Care: Proper care of the skin lesions to prevent further infection and promote healing.
3. Immunosuppressive Therapy: Consider corticosteroids or other immunosuppressive agents for the treatment of bullous pemphigoid, under the guidance of a dermatologist.
4. Supportive Care: Including pain management, nutritional support, and monitoring for potential complications.
5. Multidisciplinary Approach: Involving dermatology, infectious disease specialists, and potentially oncology, given the patient's tumor history.