bɪkˈʌz pˈɪɾɪŋ ɪz kˈɔːzd baɪ dᵻfˈɛktɪv lˈeɪɚɹɪŋ ʌvðə sˈuːpɚfˈɪʃəl nˈeɪl plˈeɪt baɪ ðə pɹˈɑːksɪməl nˈeɪl mˈeɪtɹɪks, ˌɛni lˈoʊkəlˌaɪzd dˌɜːmɐtˈaɪɾɪs ˈiː.dʒˈiː., ætˈɑːpɪk dˌɜːmɐtˈaɪɾɪs ɔːɹ kˈɛmɪkəl dˌɜːmɐtˈaɪɾɪs ðæt dɪsɹˈʌpts ˈɔːɹdɚli ɡɹˈoʊθ ɪn ðæt ˈɛɹiə ˈɔːlsoʊ kæn kˈɔːz pˈɪɾɪŋ.
Because pitting is caused by defective layering of the superficial nail plate by the proximal nail matrix, any localized dermatitis (e.g., atopic dermatitis or chemical dermatitis) that disrupts orderly growth in that area also can cause pitting.