Why medical care market is different?

Like Muskin (1958), Kenneth Arrow's 1963 paper* is also considered as a pioneer in analyzing health issues using economic perspectives. In the paper, Arrow explained some special characteristics that make medical (health) care market different from the other markets:

1. The nature of demand. Demand for medical services is irregular and unpredictable. Medical services, apart from preventive services, afford satisfaction only in the event of illness, a departure from the normal state of affairs.
2. Expected behavior of the Physician. A physician's behavior is supposed to be governed by a concern for the customer's (patient's) welfare, and regulated by a certain ethical codes, more than other profession.
3. Product uncertainty. One consumes a medical service in expectation of recovery from illness. However, when we consume a medical service, we can not predict whether it will result in a recovery (and if it does, how long will it take).
4. Supply conditions. Entry to the medical profession is restricted by licensing. It means supply is limited, hence increasing cost.
5. Pricing. The nature of medical service enables seller to effectively (and extensively) discriminate price by, among other things, consumer's income.

For sure, it doesn't mean that medical care market is the only market with special characteristics. Financial, labor, credit, and many other markets have different characteristics that depart from traditional, text-book competitive market.

*Kenneth J. Arrow, "Uncertainty and the Welfare Economics of Medical Care," The American Economic Review 53(5):940-73.