Clubbing
The medical history of digital clubbing was documented by South African cardiologist Leo Schamroth, who observed changes in his own swollen fingers while recovering from endocarditis surgery. Schamroth noted that the characteristic “window” between his fingers reappeared 2 months after the infection was controlled, though it took several more months for the distal nail’s bulbous appearance to return to normal. This clinical sign, now known as the “Schamroth Sign,” is recognized as an indicator of underlying disease, although other bedside examinations can detect clubbing with better consistency and reliability. (Myers & Farquhar, 2001)
Lovibond Angle:
The Lovibond angle is a well-known clinical sign of digital clubbing. This is the angle between the proximal nail fold and the nail at the nail’s exit. Normally, this angle is less than 180 degrees. An angle greater than 180 degrees indicates true digit clubbing.
Schamroth Sign:
Another clinical sign of digital clubbing is the Schamroth sign, as described by Schamroth. This involves the obliteration of the diamond-shaped window that is normally seen between opposing fingers. The disappearance of this window is considered a sign of digital clubbing.
Degree | Feature |
1° Clubbing | Increased fluctuation of nail bed with loss of onychodermal angle |
2° Clubbing | Above + Increased AP and transverse diameter as well as nails becomes smooth and glossy due to loss of longitudinal ridges |
3° Clubbing | Above + increased pulp tissue |
4° Clubbing | Above + features of hypertrophic Osteoarthropathy |
Type of Clubbing | Common Causes | Visual Description |
Unilateral Clubbing | – Vascular abnormalities (e.g., aneurysm, arteriovenous malformations) – Trauma or localized infection – Neoplasm (e.g., localized lung tumor) | Swelling in one finger/foot only |
Bilateral Clubbing | – Pulmonary diseases (e.g., lung cancer, bronchiectasis, cystic fibrosis) – Cardiac diseases (e.g., congenital cyanotic heart disease) – Gastrointestinal diseases (e.g., IBD, cirrhosis) | Swelling in both hands or feet |
Unidigital Clubbing | – Localized infection – Trauma – Neoplasm affecting one digit | Swelling in a single finger |
Differential Clubbing | – Coarctation of the aorta (causing clubbing in lower extremities only) – Arterial abnormalities or thrombosis affecting circulation to certain limbs | Clubbing in some extremities only |
Painful Clubbing | – Hypertrophic osteoarthropathy (associated with lung cancer, mesothelioma) – Chronic infections (e.g., lung abscesses, empyema) – Severe congenital heart disease | Redness, swelling, and tenderness in clubbed fingers |
