One of the prevailing physical signs of cystic fibrosis is noticeable digital clubbing. Digital clubbing is a condition in which the tips of fingers or toes have an unusually large amount of excess tissue. This results in the nail bed taking on a curved appearance. This rounding of the fingertips is easily recognized by viewing the fingers from the side, or by looking at the palm straight on. CF patients usually acknowledge this trait with a sense of humor, saying their fingertips look like the character "E.T." or even that their fingers have a certain "gecko-like" quality.
The precise cause of this condition is uncertain, although it occurs in people with other serious lung disease such as emphysema, lung cancer, or bronchiectasis. It is suspected that the formation of the excess tissue has something to do with the body's imbalance of proteins that stimulate muscle growth. This seems to make sense especially for cystic fibrosis patients who are usually deficient in calcium--a nutrient required not only for bone strength, but for the proper formation and function of muscle tissue.
Digital clubbing is usually present throughout a person's life. It is not an accurate gauge of the severity of lung damage in cystic fibrosis patients. The extent of the clubbing is different for almost every individual, and doesn't progress as the disease progresses. There is no way to treat or reverse digital clubbing, but it is also a benign symptom. Aside from possible embarrassment at the appearance of clubbed fingers or toes, there are no adverse effects linked to digital clubbing.
Some women with digital clubbing may find that acrylic nails do not fit well on their natural nails. Keeping the fingernails short and neat is one way to keep them from appearing too drastically different or "odd" compared to those who have flat nail beds and fingertips.