(i) Pastes generally contain a large amount (50%) of finely powdered solids. So they are often stiffer than ointments.
(ii) When applied to the skin pastes adhere well, forming a
thick coating protects and soothes inflamed and raw surfaces and minimizes the
damage done by scratching in itchy conditions such as chronic eczema. It is
comparatively easy to confine pastes to the diseased areas. In contrast, ointments,
which are usually less viscous, tend to spread onto healthy skin, and this may
result in sensitivity reactions if the preparations contain a powerful
medicament such as dithranol.
(iii) Because the powder contents pastes are porous; hence,
perspiration can escape. Since the
powders absorb exudate, pastes with hydrocarbon base are less macerating than
ointments with a similar base.
(iv) They are less greasy than ointments but since their
efficacy depends on maintaining a thick surface layer they are far from
attractive cosmetically.
(v) Most pastes are unsuitable for treating scalp
conditions because they are difficult to remove from the hair.