In what cases is Ethical Committee approval not necessary for a study? We intend to perform a study with a device we developed (approved for medical research). The tests are non-invasive and only require a very low power laser to be exposed to the skin (complying with all the existing norms).

People will have to travel from their place to our facilities periodically to perform this test.

We want to publish the results of our study, but we are afraid that at the end the journal might require an ethical committee approval (which costs a lot of time and money).

In what cases shouldn't be necessary an ethical committee approval?
Are there dermatology journals where this is not an issue for publication?
The exact regulations differ per country, but prospective studies with human subjects almost always need approval.

Since you tagged your question with "Netherlands", the relevant law is the WMO = "Wet medisch-wetenschappelijk onderzoek met mensen". Any research that falls under this law requires approval.


  Research falls under the WMO if the following criteria are met:
  
  
  It concerns medical/scientific research and
  Participants are subject to procedures or are required to follow rules of behaviour
  


There is a lot of information on the website of the Central Committee on Research Involving Human Subjects (CCMO).

You can usually also apply for a waiver from the IRB (at least in the Netherlands). You submit a request with a description of your intended research and the IRB will review your plans to determine whether your research does fall under the WMO and needs approval, or whether this requirement can be waived.

From the description of your plans, it seems likely that you need approval. Not having approval would not only mean that journals won't accept your paper, it would also mean that you'd be doing something illegal.