What is the treatment recommendation for a female patient in her late 50s with pruritis (itching) and scabs on her face and scalp, who did not respond to topical hydrocortisone but showed improvement with a short course of cephalexin (cephalexin)?

Treatment Recommendation for Pruritic Facial and Scalp Lesions with Scabs Responsive to Cephalexin

This patient has a secondary bacterial infection (impetiginization) of an underlying dermatologic condition, and requires a full course of oral antibiotics targeting Staphylococcus aureus and Streptococcus species, combined with appropriate topical corticosteroids once infection is controlled.

Immediate Management: Antibiotic Therapy

The clinical response to cephalexin confirms bacterial infection as the primary driver of symptoms. Continue or restart oral cephalexin 500 mg four times daily for 10 days 1. The failure of topical hydrocortisone alone indicates that infection, not pure inflammation, is the predominant pathology—topical steroids can worsen infection when used without concurrent antimicrobial therapy 2.

Antibiotic Selection Rationale:

• Cephalexin remains highly effective for staphylococcal and streptococcal skin infections with cure rates exceeding 90% 3, 4
• S. aureus is the most common pathogen in impetiginization of facial dermatoses 1
• Alternative agents if cephalexin is not tolerated: dicloxacillin 500 mg four times daily, or clindamycin 300 mg three times daily 1
• Do not use cephalexin twice daily for active infection—while twice-daily dosing may work for mild cases, four-times-daily dosing ensures adequate coverage for facial infections 3, 4

MRSA Consideration:

• MRSA coverage is not indicated unless there is purulent drainage, abscess formation, or history of injection drug use 1
• The response to cephalexin (a beta-lactam) confirms this is not MRSA 1

Sequential Topical Therapy After Infection Control

Once bacterial infection is controlled (typically after 5-7 days of antibiotics), address the underlying inflammatory dermatosis:

Topical Corticosteroid Selection by Location:

• For the face: Use only low-potency corticosteroids such as hydrocortisone 2.5% cream twice daily to avoid skin atrophy and telangiectasia 2
• For the scalp: Escalate to moderate-potency agents such as triamcinolone acetonide 0.1% solution or mometasone furoate 0.1% lotion twice daily 2, 5
• Critical pitfall: Never use high-potency corticosteroids on the face, and limit scalp treatment to 4 weeks maximum without dermatology supervision 2

Adjunctive Topical Measures:

• Apply emollients liberally after bathing to restore skin barrier function 1, 2
• Consider topical menthol 0.5% preparations for additional pruritus relief 2
• Avoid harsh soaps and use dispersible cream as soap substitute 1

Symptomatic Management of Pruritus

• For daytime pruritus: Fexofenadine 180 mg daily or loratadine 10 mg daily 2
• For nocturnal pruritus: Hydroxyzine 25-50 mg or diphenhydramine 25-50 mg at bedtime 2
• Avoid non-sedating antihistamines alone as they have minimal benefit for inflammatory pruritus 1

Critical Clinical Pitfalls to Avoid

1. Never intensify topical corticosteroids during active infection—this will worsen bacterial proliferation 2
2. Do not use short antibiotic courses for facial infections—the initial "short course" was inadequate; complete 10 days unless clinical cure is achieved by day 5 1
3. Rule out underlying conditions: Check for seborrheic dermatitis, atopic dermatitis, or contact dermatitis as the predisposing factor 1, 5
4. Avoid calamine lotion or topical capsaicin—these lack proven efficacy 2

Follow-Up and Escalation

• Reassess after 2 weeks 1, 2
• If no improvement despite appropriate antibiotics and topical therapy, refer to dermatology for consideration of:
  • Bacterial culture and sensitivity testing 1
  • Biopsy to rule out alternative diagnoses 5
  • Systemic immunomodulatory therapy if severe refractory inflammatory component 1

Treatment Algorithm Summary

1. Days 1-10: Oral cephalexin 500 mg four times daily
2. Days 1-5: Emollients only, no topical steroids
3. Days 5-10: Add location-appropriate topical corticosteroids once infection improving
4. Throughout: Oral antihistamines for pruritus control
5. Week 2: Reassess; if not improved, refer to dermatology