Can the skin condition keratosis pilaris be caused or worsened by hygiene or diet? (dermatology)

KP is an inherited. skin disorder. It is due to plugging of follicles so using topicals that exfoliate will help a lot, (scrubs, lactic acid, urea) foods typically do not affect it.
No. Kp is a common, benign, autosomal dominant genetic condition that affects about 40% of the population. There is no credible data that diet affects kp at all. There are anecdotal reports that vitamin a supplementation helps, but no evidence that vitamin a levels are low in patients with kp. Any relationship to gluten is conjecture at best.
Yes, diet. Keratosis pilaris may be genetic and can triggered by vitamin deficiencies, food sensitivities, and allergies. Certain vitamins like vitamin a and d can be helpful in treating kp. Cetain dietary changes, such as gluten-free, dairy-free and sugar-free might be useful in the treatment as well. Testing vitamin levels and reactions to food would be useful for coming up with a plan of action.
Possibly. Kp can appear more exaggerated in dry, pale skin. Facial kp can be more exaggerated with spicy food, or other foods that can cause flushing (ie wine, cheese, sour).