Can ringworm become crusty?

Ringworm and Crusty Lesions

Yes, ringworm infections commonly develop crusty lesions as part of their clinical presentation. Ringworm (dermatophytosis or tinea) typically presents with scaly, crusty patches that may become more pronounced as the infection progresses 1.

Clinical Presentation of Ringworm

Ringworm infections typically progress through several stages:

1. Initial presentation: Flat, scaly patches that may be red or discolored
2. Progressive stage: Development of raised, ring-shaped borders with central clearing
3. Advanced stage: Formation of crusty, scaly lesions, particularly at the edges of the infection 1, 2

The crusty appearance is particularly notable in cases where:

• The infection has been present for an extended period
• There has been scratching or trauma to the area
• Secondary bacterial infection has occurred
• The infection has been inappropriately treated with topical steroids 2, 3

Types of Ringworm and Their Crusty Presentations

Different types of ringworm can present with varying degrees of crusting:

• Tinea corporis (body ringworm): Often presents with well-defined circular lesions with raised, crusty borders 1
• Tinea capitis (scalp ringworm): May develop thick, crusty patches called "kerions" that can ooze fluid
• Tinea pedis (athlete's foot): Can develop fissures and crusting, especially between toes
• Tinea cruris (jock itch): May have less crusting but still develops scaly borders

Factors That Enhance Crusty Appearance

Several factors can make ringworm appear more crusty:

• Inappropriate steroid use: Application of topical steroids to ringworm can create "tinea incognito," which often has an atypical, more crusty appearance 2, 3
• Chronic infection: Long-standing infections tend to develop thicker, more crusty lesions 4
• Secondary infection: Bacterial superinfection can lead to increased crusting and exudate
• Scratching: Mechanical trauma from scratching can lead to thickened, crusty lesions 4

Warning Signs and Complications

Pay attention to these concerning features in crusty ringworm lesions:

• Excessive crusting with pus or drainage: May indicate secondary bacterial infection
• Expanding or non-healing lesions: Could suggest inappropriate treatment or misdiagnosis
• Development of ulceration: In rare cases, chronic untreated ringworm with repeated trauma from scratching can lead to serious complications, including malignant transformation (Marjolin's ulcer) 4

Treatment Considerations

For crusty ringworm lesions:

1. Topical antifungals: First-line treatment for most ringworm infections includes topical terbinafine, which relieves itching, burning, cracking, and scaling 1

2. Avoid corticosteroids: Using corticosteroids on ringworm can worsen the infection and create atypical presentations. Combination antifungal-corticosteroid products should be used with caution and only for short periods (less than 2 weeks) 2

3. Consider oral therapy: Extensive, thick, or crusty lesions may require oral antifungal medications for effective treatment

4. Environmental management: Since ringworm can be transmitted through contact with infected animals or contaminated surfaces, proper hygiene and environmental cleaning are essential 5, 6

Prevention

To prevent ringworm infections:

• Practice good hand hygiene, especially after handling animals
• Avoid sharing personal items like towels, combs, or clothing
• Keep skin clean and dry
• Promptly treat any skin infections to prevent spread
• Exercise caution when in contact with animals, particularly in petting zoos or with pets showing skin lesions 5

Remember that proper identification and timely treatment of ringworm infections are essential to prevent the development of thick, crusty lesions and potential complications.