What is the likely diagnosis and management for a 50-year-old patient with swelling over the face, bilateral pedal edema, fever with chills, and a history of itching, who was recently treated with prednisolone (20mg for 5 days) and anti-allergic drugs, with no known comorbidities?

Likely Diagnosis and Management

This patient most likely has cellulitis or erysipelas with possible drug-induced hypersensitivity reaction, and should be started immediately on antibiotics active against streptococci (such as cephalexin or cefazolin) while discontinuing any potential allergenic medications. 1

Clinical Assessment

Key Diagnostic Features to Evaluate

The presentation of facial swelling, bilateral pedal edema, and fever with chills following recent prednisolone use requires immediate differentiation between:

• Infectious etiology (cellulitis/erysipelas): Look for erythema, warmth, tenderness, and well-demarcated borders on the face and lower extremities 1
• Drug-induced hypersensitivity: The timing (1 month after initial itching, 5 days of prednisolone, then new symptoms) raises concern for drug reaction with eosinophilia and systemic symptoms (DRESS) or other severe cutaneous adverse reactions 2
• Angioedema: Assess for tongue/throat swelling, respiratory distress, or urticaria 1

Critical Examination Points

• Skin examination: Assess for percentage of body surface area involved, presence of bullae, skin sloughing, or mucosal involvement to rule out Stevens-Johnson syndrome/toxic epidermal necrolysis 3
• Vital signs: Document fever pattern, blood pressure (hypotension suggests anaphylaxis), and oxygen saturation 1
• Laboratory workup: Complete blood count with differential (look for eosinophilia >1500 cells/μL), liver function tests, renal function, and inflammatory markers 2

Immediate Management Algorithm

Step 1: Rule Out Life-Threatening Conditions

If any signs of anaphylaxis (throat swelling, respiratory distress, hypotension, wheezing):

• Administer epinephrine 0.3-0.5 mg intramuscularly in the anterolateral thigh immediately 1
• Provide supplemental oxygen and transport to emergency department 1
• Discontinue all suspected medications 2, 3

If extensive skin involvement (>30% body surface area with bullae/sloughing):

• Suspect Stevens-Johnson syndrome/TEN and permanently discontinue all suspected drugs 3
• Hospitalize immediately for supportive care including fluid management, wound care, and infection prevention 3

Step 2: Treat Presumed Cellulitis/Erysipelas

For patients able to tolerate oral medications:

• Start cephalexin, dicloxacillin, or clindamycin (if penicillin allergy) 1
• 5 days of antibiotic treatment is as effective as 10 days for uncomplicated cellulitis 1
• Elevate affected extremities to promote drainage of edema 1

For severely ill patients or those unable to take oral medications:

• Administer intravenous nafcillin, cefazolin, or vancomycin (if life-threatening penicillin allergy) 1
• Consider adding systemic corticosteroids (30 mg prednisolone with 8-day taper) as adjunct therapy to hasten resolution, though this must be weighed against potential drug hypersensitivity 1

Step 3: Address Drug Hypersensitivity

Discontinue prednisolone and antiallergic drugs immediately if drug reaction is suspected 2, 3

For confirmed drug-induced hypersensitivity with systemic symptoms:

• Administer intravenous methylprednisolone 0.5-1 mg/kg if severe (paradoxically, corticosteroids treat DRESS despite potentially causing it) 1, 2
• Add H1 and H2 antihistamines (famotidine, diphenhydramine) for symptomatic relief 2
• Monitor for cross-reactivity with structurally similar drugs 2, 4

Step 4: Supportive Care

• Topical management: Apply emollients and mild-to-moderate potency topical corticosteroids to affected skin areas (avoid high-potency on face) 5, 6
• Antihistamines: Consider oral antihistamines (cetirizine 10 mg or fexofenadine 180 mg) for pruritus 1
• Treat underlying conditions: Address any tinea pedis, venous insufficiency, or lymphedema that may predispose to recurrent cellulitis 1

Critical Pitfalls to Avoid

• Do not assume swelling is solely infectious: The combination of facial and bilateral pedal edema with recent drug exposure warrants consideration of drug hypersensitivity, nephrotic syndrome, or other systemic causes 7, 2
• Do not prescribe antibiotics for presumed secondary infection without evidence: Cellulitis-associated swelling is inflammatory, not infectious, unless there are clear signs of purulence or systemic infection 1
• Do not continue prednisolone if drug reaction is suspected: Paradoxically, while corticosteroids treat hypersensitivity reactions, they can also cause them; immediate discontinuation is essential if the drug is the culprit 8, 2, 4
• Do not use crotamiton cream or topical capsaicin for pruritus: These are ineffective and not recommended 1

Follow-Up Considerations

• If cellulitis recurs frequently: Consider prophylactic antibiotics (monthly benzathine penicillin 1.2 MU IM or oral penicillin V 1 g twice daily) 1
• If drug hypersensitivity confirmed: Perform skin testing (intradermal testing more sensitive than skin prick test) to identify safe alternative medications before future use 4
• Monitor for complications: Each cellulitis episode causes lymphatic damage; implement preventive measures including compression stockings, elevation, and skin hydration with emollients 1