What is the diagnosis and treatment for crusty lesions at the corner of the lips and a similar coin-sized lesion on the arm?

Diagnosis and Treatment of Crusty Lip and Arm Lesions

Most Likely Diagnosis: Angular Cheilitis with Secondary Impetigo

The presentation of crusty lesions at the corner of the lips with a similar coin-sized lesion on the arm most likely represents angular cheilitis with secondary bacterial spread (impetigo), requiring combination antifungal-corticosteroid therapy for the lip lesions and topical/systemic antibiotics for the bacterial component. 1

Diagnostic Approach

Key Clinical Features to Assess

• Lip lesion characteristics: Angular cheilitis typically presents with erythema, fissuring, and crusting at the oral commissures, often with mixed Candida and bacterial infection 1, 2
• Arm lesion characteristics: A coin-sized crusty lesion suggests either bacterial spread (impetigo) or, less likely, a separate dermatologic process 3
• Underlying risk factors: Evaluate for ill-fitting dentures, loss of vertical dimension, diabetes, immunosuppression, medications causing xerostomia, and habits like lip licking 1
• Systemic symptoms: Absence of fever and systemic symptoms makes severe conditions like Stevens-Johnson syndrome unlikely 3

Important Differential Diagnoses to Exclude

• Herpes simplex: Would show vesicles progressing to crusts, typically resolves in 7-10 days, and requires antiviral therapy if active 3, 4
• Impetigo: Honey-colored crusts, highly contagious, requires antibiotic therapy 3
• Leishmaniasis: Consider if travel history to endemic areas (Old World or New World), presents as ulcerative lesions with raised borders 3
• Lichen planus: Erosive form can affect lips but typically has reticular white patterns and is chronic 5
• Factitious disorder: Bizarre hemorrhagic or keratotic crusts with underlying psychiatric issues 6

Treatment Algorithm

First-Line Treatment for Angular Cheilitis

Combination antifungal-corticosteroid therapy addresses both the Candida infection and inflammatory component 1:

• Antifungal component: Nystatin oral suspension (100,000 units four times daily for 1 week) OR miconazole oral gel (5-10 mL held in mouth after food four times daily for 1 week) 1
• Corticosteroid component: Topical corticosteroid to reduce inflammation 1
• For resistant cases: Fluconazole 100 mg/day for 7-14 days 1

Treatment for Secondary Bacterial Infection (Arm Lesion)

If the arm lesion represents bacterial spread (impetigo):

• Topical antibiotics: For localized lesions 3
• Systemic antibiotics: If extensive or not responding to topical therapy, minimum 72 hours of antibiotic therapy with lesions resolving 3
• Antiseptic measures: Chlorhexidine oral rinse twice daily for oral bacterial component 1

Essential Supportive Measures

• Emollient application: White soft paraffin ointment to lips every 2-4 hours 1, 7, 8
• Oral hygiene: Warm saline mouthwashes daily 1
• Anti-inflammatory rinses: Benzydamine hydrochloride rinse or spray every 3 hours, particularly before eating 3, 1
• Avoid irritants: Spicy foods, hot foods/drinks, citrus fruits 7, 8

Follow-Up and Reassessment

• If no improvement after 2 weeks: Reevaluate diagnosis and patient compliance 1
• Consider biopsy if: Lesions persist despite appropriate therapy, to rule out premalignant conditions (actinic cheilitis) or other diagnoses 1, 9
• Immunocompromised patients: May require more aggressive and prolonged therapy 1

Critical Pitfalls to Avoid

• Do not use petroleum-based products chronically on lips as they promote mucosal dehydration and create an occlusive environment increasing secondary infection risk 1
• Do not miss leishmaniasis if patient has travel history to endemic areas; this requires species identification and specific systemic therapy 3
• Do not overlook underlying systemic conditions: Diabetes, immunosuppression, nutritional deficiencies that perpetuate angular cheilitis 1, 2
• Do not treat with local therapy alone if leishmaniasis is suspected with risk for mucosal involvement (New World species from Costa Rica southward) 3

When to Consider Alternative Diagnoses

If lesions show these features, reconsider diagnosis:

• Ulcerated lesions with raised borders and travel to endemic areas → Leishmaniasis (requires tissue diagnosis, culture, and molecular testing) 3
• Vesicular lesions with rapid progression → Herpes simplex (requires antiviral therapy for minimum 5 days) 3
• Extensive mucosal involvement with systemic symptoms → Stevens-Johnson syndrome (requires immediate hospitalization) 3