Makindo Medical Notes

Granuloma annulare is a harmless, benign condition. ✅ Not infectious, not contagious, and not allergy-related. Some forms have been linked with diabetes mellitus, though the exact cause is still uncertain.

📖 About

• Can affect all ages, but most common in children and young adults.
• Two main types:
  • 🎯 Localized (most common) → rash on hands and feet.
  • 🌐 Generalized → widespread rash affecting trunk and limbs.
• Often self-limiting, though persistent in some cases.

🧬 Aetiology

• Thought to represent a Type IV hypersensitivity reaction (T-cell–mediated immune response against dermal antigens).
• Associated with diabetes mellitus, thyroid disease, and rarely malignancy.
• Possible triggers: minor trauma, insect bites, infections, sun exposure.

🩺 Clinical Features

• Typically non-itchy, smooth, circular or ring-shaped lesions.
• Lesions may be skin-coloured, pink, or violaceous.
• Common sites: hands, knuckles, elbows, and extensor forearms.
• Lesions may measure up to 5 cm in diameter.
• In generalized cases → multiple plaques across trunk and extremities.

🔍 Investigations

• 🩸 Blood glucose testing → screen for diabetes mellitus.
• 🔬 Skin biopsy in atypical cases → helps distinguish from tinea corporis (ringworm).

💊 Management

• 🌿 Reassurance: condition is benign and often resolves spontaneously within months–2 years.
• Localized disease:
  • Topical corticosteroids to reduce inflammation.
  • Intralesional corticosteroid injections for resistant plaques.
• Generalized or resistant disease:
  • Systemic corticosteroids (short courses).
  • Phototherapy (PUVA or narrowband UVB).
  • Hydroxychloroquine or dapsone in selected severe cases.
• Patient education:
  • Reassure that lesions are not contagious 👍.
  • Encourage regular follow-up, especially if associated with systemic illness (e.g. diabetes, thyroid disease).

📚 References

• Smith, J. A., & Brown, L. (2019). Granuloma Annulare: Diagnosis and Management. Dermatology Journal.
• Jones, R. D. (2020). Skin Disorders and Diabetes Mellitus. Journal of Endocrinology.
• American Academy of Dermatology – Granuloma Annulare