The high temperature, high humidity, strong sunlight, and the fact that plants and animals in the environment are in a vigorous reproduction period, combined with the large amount of human sweating and the increase in exposed parts of the skin, make summer a high season for dermatological diseases, and the number of dermatology outpatient visits increases dramatically every summer. What are the specific skin diseases that have a high incidence in summer? Solar dermatitis is a skin disease in which the body reacts strongly to sunlight. It is mostly seen in fair-skinned people, individuals who are sensitive to light, or caused by the intake of photosensitive foods (such as celery, etc.), drugs (such as ofloxacin, etc.), etc. Skin manifestations include erythema, papules, blisters, swelling, and itching in exposed areas. Prickly heat is caused by a large amount of sweat that does not evaporate easily in a hot and muggy environment. The lesions are often found in groups and appear as densely arranged pinpoint papules or papules surrounded by a red halo. Summer dermatitis Heat dermatitis caused by continuous high temperature and high humidity, mostly seen in adults. It often affects the flexors and trunk of the extremities, especially the bilateral anterior shins, and is symmetrically distributed. The manifestation is pinpoint size erythema, papule, papule, itching, scratching can appear scratch marks, skin hypertrophy, pigmentation. It may subside in cooler weather. Skin diseases caused by fungal infections The temperature of 22~28℃ and medium humidity are most suitable for the growth and reproduction of superficial skin fungi, so the incidence of fungal diseases is significantly higher in summer than in other seasons. Examples include tinea cruris, tinea pedis (commonly known as tinea pedis), ringworm, and sweat spots. Ringworm of the hands and feet can manifest as red papules and blisters, rough flaking, whitish maceration, and erosion. Itching is usually obvious, and scratching the skin can easily cause bacterial secondary infections. Patients often suffer from aggravation and recurrence of the disease due to erroneous topical application of hormonal medications. Pemphigus foliaceus (sweat spot) mostly occurs on the neck, forehead, back of the shoulder, upper arm, and armpit. It can be brown, light brown, light red, light yellow or white, gradually increasing to the size of a fingernail, round or similarly rounded, with no obvious discomfort and occasional slight itching. Insect bite skin diseases caused by insects, mosquitoes, poisonous moths, caterpillars, mites and other bites, the skin appears itchy papules, wind clusters, erythema, blisters, etc. Cryptoptera dermatitis is a dermatitis caused by the strong acidic venom inside the insects after the insects are beaten or crushed when they rest on the skin. After a few hours to 2 days of exposure to the venom, localized edematous erythema in the form of streaks, sheets or clusters of spots with dense papules, blisters and pustules, with itching, burning and burning sensation. Papular urticaria is an allergic skin reaction caused by insect bites, manifesting as red papules or macules with intense itching and, in severe cases, blisters or macules. It is mostly seen on the extremities, waist, and other bites, and can also produce extensive, recurrent lesions.