Netherton syndrome is a rare autosomal recessive disease characterized by erythroderma, ichthyosis linearis circumflexa, atopy, failure to thrive and a specific hair shaft abnormality called trichorrhexis invaginata or bamboo hair, considered pathognomonic. We report the case of a 4-year-old boy with erythroderma since birth, growth deficit and chronic diarrhea. Trichoscopy was used to visualize typical bamboo and "golf tee" hair and of key importance to diagnose Netherton syndrome. We suggest the use of this procedure in all children diagnosed with erythroderma.