Seasonal light erythematous patches, also called peach fungus, are called seasonal contact dermatitis in Western medicine. The disease occurs on the face of women and starts as flushed or light red coin-like patches with a few small red papules with indistinct borders and a small amount of scales attached. Itchiness or dryness is felt. Sometimes accompanied by a history of allergic rhinitis or other allergic diseases. So, what are the symptoms of seasonal light erythematous patches? How should it be diagnosed? The following is a brief description of the diagnosis: According to the patient’s seasonal onset in spring, recurrent, manifested as mild erythema, papules, scales on the face, without a clear history of allergenic substance exposure (the patient himself often can not perceive what kind of allergenic substance exposure is caused), a preliminary diagnosis can be made. This disease is a seasonal recurrent contact dermatitis caused by pollen, which occurs in spring and autumn, and is more common in women. The clinical manifestations are seasonal and sudden, the rash is mostly confined to the face and neck, showing mild erythema, edema, slightly elevated or accompanied by a few rice-grain-sized red papules; some show erythema around the eyes or neck, edema is not obvious; some can also be eczema-like changes, mildly mossy rash, sometimes with furfur-like scales. It is often accompanied by pruritus, which recurs every year and may subside on its own. The disease is sometimes associated with a history of allergic rhinitis or other “atopic” conditions. Allergen testing and serum IgE assay may be useful for diagnosis.