Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in determining the cause of the allergic response. Antihistamines, mast cell stabilizers or dual activity drugs are safe and usually effective. Corticosteroids are reserved for more severe cases of inflammation, and their use should be monitored by an optometrist due to possible side-effects. When an allergen is identified, the person should avoid the allergen as much as possible. Non-pharmacological methods
If the allergen is encountered and the symptoms are mild, a cold compress or artificial tears can be used to provide relief. Mast cell stabilizers
Mast cell stabilizers can help people with allergic conjunctivitis. They tend to have delayed results, but they have fewer side-effects than the other treatments and last much longer than those of antihistamines. Some people are given an antihistamine at the same time so that there is some relief of symptoms before the mast cell stabilizers becomes effective. Doctors commonly prescribe lodoxamide and nedocromil as mast cell stabilizers, which come as eye drops.A mast cell stabilizer is a class of non-steroid controller medicine that reduces the release of inflammation-causing chemicals from mast cells. They block a calcium channel essential for mast cell degranulation, stabilizing the cell, thus preventing the release of histamine. Decongestants may also be prescribed. Another common mast cell stabilizer that is used for treating allergic conjunctivitis is sodium cromoglicate. Antihistamines
Antihistamines such as diphenhydramine and chlorpheniramine are commonly used as treatment.
But because of how the linkage is set up to refer back to the sentinel, the code just works for empty lists as well, where curnode will be the sentinel node. Search in a binary tree
General declarations, similar to article Binary search tree:

The globally available pointer sentinel to the single deliberately prepared data structure Sentinel = *sentinel is used to indicate the absence of a child. Note that the pointer sentinel has always to represent every leaf of the tree. This has to be maintained by the insert and delete functions. It is, however, about the same effort as when using a NULL pointer. Remarks
With the use of SearchWithSentinelnode searching loses the R/O property. This means that in applications with concurrency it has to be protected by a mutex, an effort which normally exceeds the savings of the sentinel. SearchWithSentinelnode does not support the tolerance of duplicates. There has to be exactly one “node” to be used as sentinel, but there may be extremely many pointers to it. See also
Sentinel value
Magic number (programming)
Magic string
Null object pattern
Time formatting and storage bugs
Elephant in Cairo
Canary value
Semipredicate problem


== References ==