Skin & fur problems commonly go together with any immune & digestive system issues, but can also happen due to hormonal changes (puberty, estrus, or abnormal processes) or aggressive environmental factors. Among those could be acne, superficial inflammation, partial alopecia (bald patches of skin), etc. Not all of them require specialized treatment, but to conclude whether the treatment is needed or not, you need to understand common correlations between the underlying causes of specific symptoms.
Most often skin & fur problems appear at periods of decreased immunity functions or/and emotional stress (moving to a new home, vaccination, seasonal changes, injuries, and illnesses) and active hormonal changes (puberty, proestrus). Together with partial alopecia (areas of bald skin), during diagnostics, you can often find demodex - it's a part of a normal skin ecosystem, which becomes hyperactive when found a “hole” in the immune system. To avoid its manifestations, it is important to remember the importance of both genetics and home care influences in the formation of functional immunity and not rush to artificially suppress it.