In DPB, the nodules are more restricted to the respiratory bronchioles, while in OB they are often found in the membranous bronchioles (the initial non-cartilaginous section of the bronchiole, that divides from the tertiary bronchus) up to the secondary bronchus. OB is a bronchiolar disease with worldwide prevalence, while DPB has more localized prevalence, predominantly in Japan. Prior to clinical recognition of DPB in recent years, it was often misdiagnosed as bronchiectasia, COPD, IPF, phthisis miliaris, sarcoidosis or alveolar cell carcinoma. Treatment
Macrolide antibiotics, such as erythromycin, are an effective treatment for DPB when taken regularly over an extended period of time. Clarithromycin or roxithromycin are also commonly used. The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through immunomodulation (adjusting the immune response), which can be achieved by taking the antibiotics in low doses. Treatment consists of daily oral administration of erythromycin for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and blood gas (an arterial blood test that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range. Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant P. aeruginosa.
Brachioradial pruritus (sometimes abbreviated BRP) is an intense itching sensation of the arm usually between the wrist and elbow of either or both arms. : 36   The itch can be so intense that affected individuals will scratch their own skin to a bleeding condition. The condition is becoming increasingly common, presenting in patients who are usually fair skinned and middle aged and indulge in golf, tennis, outdoor table tennis, sailing,  or other leisure outdoor activities in sunny climates. : 64 : 402 The cause is not known, although there are a few lines of thought on what causes it. No cure has been found, but depending on severity, good control with treatment can be achieved. For milder cases, the intense itch/scratch cycle can be broken by applying a topical skin coolant gel containing menthol, camphor, or other topical coolant to affected itchy areas, and then consistently applying 100+SPF sunscreen to affected skin of arms, shoulders, neck, etc., whenever they are expected to be exposed to the sun. A unique prescription topical combination of ketamine .5% and amitriptyline hydrochloride 1% has shown immediate and long term relief with no serious adverse events in at least one severe case. [1]
Many different medications and types of topical creams have been experimented with, but few seem to make any difference, except for the above. The application of ice packs to the affected area can also diminish the itch short-term. Causes
Brachioradial pruritus (BRP) is a localized pruritus of the dorsolateral aspect of the arm.