For example, ICD-10 classifies "vasculitis limited to skin" with skin conditions (under "L"), and "necrotizing vasculopathies" (corresponding to systemic vasculitis) with musculoskeletal system and connective tissue conditions (under "M"). Arteritis/phlebitis on their own are classified with circulatory conditions (under "I"). Type or size of the blood vessels that they predominantly affect. Apart from the arteritis/phlebitis distinction mentioned above, vasculitis is often classified by the caliber of the vessel affected. However, there can be some variation in the size of the vessels affected.A small number have been shown to have a genetic basis. These include adenosine deaminase 2 deficiency and haploinsufficiency of A20. According to the size of the vessel affected, vasculitis can be classified into:
Large vessel: Takayasus arteritis, Temporal arteritis
Medium vessel: Buergers disease, Kawasaki disease, Polyarteritis nodosa
Small vessel: Behçets syndrome, Eosinophilic granulomatosis with polyangiitis, Cutaneous vasculitis, granulomatosis with polyangiitis, Henoch–Schönlein purpura, and microscopic polyangiitis. Condition of some disorders have vasculitis as their main feature. The major types are given in the table below:Takayasus arteritis, polyarteritis nodosa and giant cell arteritis mainly involve arteries and are thus sometimes classed specifically under arteritis. There are also many conditions that have vasculitis as an accompanying or atypical feature, including:

Rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and dermatomyositis
Cancer, such as lymphomas
Infections, such as hepatitis C
Primary Immunodeficiencies, such as DADA2, GATA2, and RAG deficiency
Exposure to chemicals and drugs, such as amphetamines, cocaine, and anthrax vaccines which contain the Anthrax Protective Antigen as the primary ingredient.
Bleb or bulla
The most common disease causing blebs or bullae is paraseptal emphysema though centrilobular emphysema may sometimes be involved. Other conditions associated with lung bullae are:
Other conditions associated with lung bullae are:

Alpha 1-antitrypsin deficiency
Marfan syndrome
Ehlers–Danlos syndromes
Cocaine smoking
Sarcoidosis
HIV/AIDS
Intravenous substance abuse

Cyst
A pulmonary cyst is not necessarily the same type of cyst seen in many cystic lung diseases. The cyst for example in pneumocystis pneumonia is not the same as the pulmonary cyst. Cystic lung diseases include:

Langerhans cell histiocytosis (LCH)
Lymphangioleiomyomatosis (LAM)
Lymphocytic interstitial pneumonia (LIP)
Birt–Hogg–Dubé syndrome
Pneumocystis pneumonia
Pulmonary amyloidosis
Light chain deposition disease
Lung metastases rarely cause multiple cystic lung lesions. This form of presentation has been described in metastatic sarcomas. Incidental blebs and cysts
A focal lung pneumatosis that is an incidental imaging finding such as on a CT scan, without suspicious findings (such as findings indicating any of the diseases listed above), generally does not indicate further follow-up. Cavity

Two infectious diseases that are commonly associated with cavities of lung tissue are Mycobacterium tuberculosis and Klebsiella pneumoniae. The formation of cavities is due to tissue necrosis and creates an environment that allows the pathogen to expand in numbers and spread further.In the absence of infectious symptoms, a lung nodule with cavitation is a suspected lung cancer. == References ==