True regarding Crohn's disease are all except
The skin involvement in Crohn's disease causes erythema nodosum, scleroderma does not occur in Crohn's disease.

Other extraintestinal manifestations of Crohn's disease:
1. Migratory polyarthritis           
2. Sacroiliitis 
3. Ankylosing spondylitis    
4. Uveitis
5.. Hepatic pericholangitis        
6. Primary sclerosing cholangitis
7. Clubbing
Scleroderma
Transmural involvement
Cobble stone appearance
Skin involvement