Ointments tend to be messier because of the petroleum base that is used in the formula while creams, lotions, gels, and straight liquid will absorb into the skin and don’t tend to get on things (such as clothing).
There are times that you will receive prescriptions for ointments, though. This is because certain medications are much more effective when a petroleum base is used rather than a water or oil base.
Creams are water or oil based and the two liquids combine, forming a suspension of oil and water in a 50/50 ratio. The medication within this base penetrates the outer layer of the skin (stratum corneum) better. Creams are very soothing as a general rule and also act as a moisturizing agent; in the case of eczema, these qualities are very helpful in alleviating the itchy skin.
Liquids are used as bath additives, paint-on medications (such as calamine lotion), gels, wet dressings, and lotions. Tar baths consist of a liquid (with tar as the active ingredient) which is added to bath water. Certain oils may be recommended as bath additives or as moisturizing agents at times. Liquids tend to dry weeping lesions best.
Ointments, which are usually petroleum based, use a combination ratio of 80/20 with the 80 being oil and the 20 being water. An 80/20 oil/water mixture is a better barrier against loss of moisture. Liquid and cream medications cannot boast the moisture locking characteristics of ointments. You may now be wondering why all dermatologists don’t just prescribe ointments since moisture retention in a main factor in alleviating eczema symptoms.
This is again due to the fact that certain medications are better in one form than they are in another, meaning that some corticosteroids will work much better as a cream or lotion than they will as an ointment. The difference is all in the delivery. Some medications need to be quickly absorbed into the skin (these are in cream or liquid form) while others work better when slowly released into the skin (ointments do this). Ointments are most often prescribed when there are very dry patches of eczema because they lock in moisture and provide a temporary, yet effective, barrier on the skin.
Pastes are a combination of oil, powder, and water. The form is known as a suspension, similar to certain children’s medications like Tylenol suspension. This form of suspension is intended to be applied to the skin, though not to be taken orally. The greasy qualities of some creams, some liquids, and all ointments and are often drying. One of the most common forms of paste as a topical medication for eczema is a suspension made up of calcium hydroxide solution, oil, and zinc oxide (which is the powder in this case).
Like lotions, pastes are best used for soothing and drying open lesions in areas affected by eczema. These should never be applied to skin creases and folds (such as the genital area, the bend of the elbow, and the backs of knees) when there are open lesions. These areas, because of the bend and friction, tend to cause the suspension to clump, which in turn, further irritates the skin and worsens the eczema in that area.
