Flat warts (verruca plana) are small, slightly raised bumps that appear in clusters. They're caused by the human papillomavirus (HPV), a group of more than 100 viral strains. HPV is the most ...

The differential diagnosis includes juvenile xanthogranuloma, verruca plana, milia and papular urticaria. Lesions usually resolve spontaneously, but this process may take years, with more ...