Milk

What's the difference between a milk allergy and lactose intolerance?

A milk allergy is an adverse immune reaction to one of the proteins found in cow's milk.

Lactose intolerance is a sensitivity that comes from a lack of the milk digesting enzyme, lactase.

A true dairy allergy could lead to anaphylaxis. Lactose intolerance does not .

Articles
Milk allergies 101  - from the online allergist
Milk allergy avoidance list- from  Kidswithfoodallergies.org
How to read a label for milk- from FAAN
Kosher Labeling- Dairy Allergies a must read from kidswithfoodallergies.org

Is Pareve Really Pareve? a great article from the CRC

Substitutions 

Rule of Thumb about Substitutes- (from KFA- kidswith foodallergies)

Whether or not a "safe" version of a recipe can be successfully made often depends on two important factors. First: what is the role of the allergen in the recipe? Second: how many of the recipe's ingredients require substitutions? If the recipe only has 5 ingredients and you need to swap out 4 of them, the end result might bear little resemblance to the original dish. The bottom line: sometimes you can create a "safe" version of a recipe, and sometimes you are better off finding a different recipe altogether.
General Kosher Substitutions from kosherscoop.com

Milk Substitution Guide -  Kidswithfoodallergies.org
Dairy Substitutes- from eatingwithfoodallergies.com
Non-Dairy Substitutes for Desserts- Jamie Geller's Joyofkosher.com

Organizations

Checkout the organizations tab of this site for comprehensive milk allergy information