Background and aim Cystic Fibrosis (CF) is the most frequent prominent fatal disease of the white race. It is estimated that about 1 in 2000–2500 children are born in Greece with cystic fibrosis every year while 4%–5% of the population are carriers of a gene. The average age of diagnosis is 7 months old and in most cases it happens in the first year of life. Sometimes symptoms are subclinical and the disease can be presented with rare signs such as clubbing of the nails, which can escape of the appropriate attention.

Methods Α thirteen year old teenager was admitted in our department for upper abdominal pain and cough. His physical development was normal and had a history of repeated bronchitis episodes. He did not have any other admissions in the hospital nor had any other symptoms. From his clinical examination he had wheezing and wet crackles, but we noticed an extensive clubbing of the nails in both hands and toes bilateral and in every finger. Parents were not aware of the abnormal morphology of the nail fingers and they had not discussed it with any other clinician. The differential diagnosis includes: Cardiac disease, endocrine disease, gastrointestinal (celiac disease, crohn’s disease ), tuberculosis, cystic fibrosis,interstitial lung disease – particularly bronchiectesis, hypertrophic osteopathy – primary and secondary, pseudoclubbing. We conducted Agia Sofia paediatric hospital in Athens in order to arrange a sweat chloride test, a chest CT and a genetic test for CF and tests to exclude the above diseases.

Result The sweat chloride test was positive for CF, as well as the genetic test revealed the ΔF508/Glu22X mutation responsible for the disease.

Conclusion Digital clubbing, despite rare in the paediatric population, is a sign that has to be evaluated and it can be almost the only obvious characteristic of a serious disease such as Cystic Fibrosis.