"The Itchy, itchy skin"

My son has been experiencing a several skin allergies even before he turned a year old and up until now that he is already ten years old. I remember rushing him to the hospital when he was only eight months old due to a very severe case of diaper. Severe in a sense that rashes formed into a shape of a diaper all over his buttocks, lower hips and crotch region which also gave him an infection on his genital area, making it red, swollen and a little pus coming out from the tip. The doctor diagnosed him of having "Cellulitis" , a skin infection by staph aureus (staphilococcus aureus) bacteria, a common bacteria we often hear which causes different type of sickness to our kids from skin infections to respiratory tract infections. Usually, it starts with a break in the skin, or in some cases, in patients which have a weak immune system. In the case of my son, it was triggered by simple diaper rash. After the bacteria sets in the skin, the child would usually get high fever, sometimes with chills and sweats. Skin upon examination would look really red, some areas with pus-like breaks, and would feel warm when toughed due to the inflammation. I could imagine that it would really feel itchy, but when scratched would be too painful for the child to bear. After my son was admitted to the hospital, he was administered with an antibiotic intravenously for faster effects.
Aside from intravenous antibiotics, the doctor also gave him an ointment with "Gentamycin" , something to be applied to the skin lesion twice a day after bath. The skin must also be cleansed with a soap free cleanser to prevent skn from getting dry, and producing further irritation.
In our case, the doctor recommended "Cetaphil", a skin product that could be used as cleanser (soap) and as moisturizer (lotion), it comes in the form of a bar or liquid, however, the liquid form is quite cheaper compared to the bar, probably because it is diluted with water unlike the bar form.
My son was treated for almost two weeks in the hospital, with continuous and rigid treatment, and with great help from the antibiotic administered intravenously, he was able to recover from cellulitis. Athough he was discharged from the hospital, and the use of the recommended cleanser, and skin antibiotic ointment continued for another week, the danger of the cellulitis coming back is close to none. Recently, however, it made me do a little research on the net regarding this skin condition and I learned a few simple additional treatments recommended by dermatologist. Some of which include elevating the area affected higher than the heart level which could actually hasten the effect of antibiotic, assist the lymphatic system in draining out the bacteria and minimize the discomforts of inflammation. Depending probably on the affected part and the severity of the lesion, an occlusive dressing is also recommended. If unfortunately, a working adult is afflicted with this condition, he will experience pain and discomfort which could prevent him from going to work, and therefore must need to stay home.
The unending quest for the cause of my son's skin condition has never been identified until now. Early on, his pediatrician suspected a food allergy caused by "yellow" foods, any food which is yelow in color like cheese, cheese powder, potatoes, even carrots but these was never ruled in or ruled out. I suspect an allergy with chicken and all poultry products, which I noticed is the most likely food allergens. Recently however, even if my son eats chicken or any poultry product, he does not seem to experience skin itchiness (which mysteriously is localized on his lower legs only). He is venturing into eating dried, salted fish and other seafoods and these also, I have noticed caused skin itchiness on his lower legs especially pronounced at night. He seems to itched the most at night during his sleep time. This usually results in skin breaks caused by severe scratching. It seems like a perennial worry for me and I am worried that it might be a cause of embarrassment for him if other children will see what his legs look like.
Right now, I am trying to minimize the effect by letting him use a sulphur soap with additional anti-bacterial properties and buying an ointment with "Fluocinolone acetonide" since it is four times cheaper than the previously used skin ointment with Gentamycin.
Right now, I am just downright thankful that the condition is under control, not threatening to spread to other skin areas, and not progressing towards the dreaded "Cellulitis", but I am still hoping and praying that this skin condition would end especially that my boy is fast approaching pre-adolescent age. I also hope that the condition would finally be diagnosed and that the root cause would finally be discovered. If given the financial budget, I would give skin patch test a try, which might be a very useful tool to identify the main culprit.