Long-term skin conditions that are common include psoriasis and atopic dermatitis. They are not highly contagious. Since both rashes have a fairly similar appearance, making the diagnosis may be challenging at first, and a skin biopsy is still the last option. Before the doctor orders a biopsy, there are a few things that can help distinguish between the two. In addition to being the most prevalent form of eczema, atopic dermatitis also has a higher prevalence than psoriasis in the US. Atopic dermatitis affects roughly 16.5 million individuals, and psoriasis affects more than 8 million people. Itchy skin with small, red pimples or a rash or red to brownish-gray areas might be a symptom of atopic dermatitis. Much more frequently and intensely itching occurs than psoriasis. The lumps may exude fluid and crust over when scratched. The illness frequently starts in childhood and can last till maturity. The cheeks, inside of the elbows, below the knees, and around the neck are typical locations for rash. Atopic dermatitis increases a person's risk of developing asthma or hay fever. Additionally, having hay fever or asthma in the family increases the likelihood of developing atopic dermatitis.