Complications and risks of ringworm

Most ringworm is a mild skin problem that clears without lasting effects. Complications are uncommon, but they can happen, mainly when the infection is untreated, treated wrongly or occurs in people with weak immunity.

Skin complications

• Bacterial infection from scratching, causing pus, swelling, warmth and pain, and sometimes cellulitis.
• Spreading of the rash to other body areas, or to family members and pets.
• Tinea incognito, a changed, widespread, hard-to-recognise rash after steroid cream use.
• Dark or light patches left on the skin for weeks to months after healing (post-inflammatory marks).
• Chronic, recurring infection, especially in the groin, feet and nails.

Scalp complications

• Hair loss that may be temporary, but can become permanent scarring if a severe inflamed form (kerion) is not treated early.
• Painful swollen lumps on the scalp and swollen neck glands.

Nail complications Nail thickening, discolouration and deformity that may be long lasting, and may take months to grow out.

Rare complications In people with very weak immunity, the fungus can invade deeper tissue (Majocchi's granuloma) or spread more widely. Allergic skin reactions known as "id reactions" can appear away from the infection site.

Higher-risk groups People with diabetes, HIV, cancer treatment, long-term steroid use or other immune problems, and young children.