Start by finding where and how the symptoms appeared
Even if skin symptoms look similar,
the details to check are different
Commonalities such as itching, redness, or scaling do not necessarily mean it is the same condition. Please check the location of the skin issue, how long it has persisted in one spot, and any changes after using medication.
If you are unsure of the diagnosis, start with what you see now
Narrow it down by the affected area and the appearance
You do not need to know the name of the condition beforehand. Find the closest condition guide by checking where it appeared, whether you see blisters, scaling, or swelling, and how long it remains in the same spot.
Information on 40 diseases in total
Pediatric · Adult · Face/Neck
Atopic Dermatitis Patterns by Age and Area
We examine nighttime itching and recurring locations by dividing atopic dermatitis according to age and lifestyle scenarios, such as skin folds in children or the face, neck, and hands in adults.
Adult Atopic Dermatitis
Adult atopic dermatitis often begins with severe itching before a rash appears; as the skin is scratched, it may turn red, brown, purple, or gray, and often becomes dry and scaly. In adults, it commonly occurs on the hands, feet, creases of the elbows, behind the knees, neck, face, and around the eyes; prolonged scratching can make the skin thick, leathery, and cracked. Oozing, blisters, or scabs may form, and nighttime itching can disrupt sleep and work. In darker skin tones, purple, gray, or brown changes or small rough bumps may be more prominent than redness. If golden scabs, pus, pain, heat, swelling, or sudden clusters of blisters and fever occur, seek prompt medical evaluation for infection or pompholyx.
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Atopic Dermatitis
Atopic dermatitis is not diagnosed by a single blood test or allergy test. The process centers on a dermatological evaluation of the appearance and distribution of dryness, itching, and rash, as well as the onset time, the course of improvement and worsening, sleep disturbance, response to previous treatments, and exposure to irritants such as soap, detergents, scented products, and smoke. Medical history of atopic dermatitis, asthma, and hay fever for the patient and their family is also reviewed. Skin examination and medical history are often sufficient, and blood tests or skin biopsies are selected when other causes of the rash must be ruled out. Symptoms, distribution, and progression are interpreted together rather than relying on a single test result.
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Childhood Atopic Dermatitis
Childhood atopic dermatitis is not diagnosed by a single photograph or a single allergy test. In infancy, it may appear on the face and torso, and as the child grows, it often becomes prominent in flexural areas such as the elbow and knee creases; therefore, the age of onset, recurring locations, nighttime itching, and family history of atopy are all considered. If there is pain, oozing, pus, or fever at the site of scratch wounds, infection is checked first.
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Face and Neck Atopic Dermatitis
Face and neck atopy is primarily characterized by dryness, itching, and recurring distribution around the eyes and neck. However, it can resemble rosacea (characterized by persistent redness, visible blood vessels, and papules in the center of the face), contact dermatitis (with clear boundaries where new cosmetics touched the skin), or seborrheic dermatitis (with oily scales near the eyebrows and sides of the nose). Rather than changing multiple products at once, it is recommended to check the shape of skin changes alongside the start date of each product.
View condition guide →Oozing · Dryness · Contact · Hands/Face
Eczema and Contact/Regional Dermatitis
Rather than stopping at 'eczema,' we categorize by contact exposure, water-related work for hands, the face/eye area, coin-shaped lesions, and areas that have been scratched for a long time.
Eyelid and Face Eczema
Eyelid and face eczema can be itchy and dry, and may cause fine scaling and stinging. Clues include not only products applied directly to the eye area but also substances that touched the skin via hands or air, such as nail products or hair dyes. If there are oily scales near the eyebrows or sides of the nose, persistent redness and papules in the center of the face, or eye pain, light sensitivity, or changes in vision, other skin and eye conditions are checked together.
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Chronic Eczema
Chronic eczema is characterized by dry and rough skin, recurring redness and itching, scaling and cracking, and skin that has become thick and hard due to prolonged scratching. Depending on skin tone, redness may be less visible or may appear darker, such as brown, gray, or purple; hands and flexural areas may crack after water work or friction, leading to pain or bleeding. If it worsens, clear oozing and crusting may occur; yellow crusts, pus, heat, a rapid increase in pain, and fever require checking for possible infection. Nighttime itching, loss of sleep, and discomfort when using hands, washing, or dressing are also significant symptom burdens.
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Hand Eczema
Hand eczema is a type of dermatitis characterized by recurring dryness, redness, scaling, stinging, and deep cracks on the back of the hands, fingers, and palms. Exposure to water, detergents, disinfectants, gloves, and occupational hazards, as well as a history of atopy, can be contributing factors. It must be distinguished from pompholyx (dyshidrotic eczema), which is characterized by deep small blisters on the sides of the fingers; tinea manuum, which presents with fine scaling on one hand and is often accompanied by athlete's foot; and contact dermatitis, which occurs at the boundaries where specific substances have touched the skin.
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Eczema
Common symptoms of eczema include dry, severely itchy skin and rashes. It can occur on the face, inside the elbows, behind the knees, and on the hands and feet; depending on skin tone, it may appear red, brown, purple, or gray, or present as prominent rough bumps. Scratching leads to swelling and increased itching, and may cause scratch marks, scales, cracking, blisters, oozing, or crusting. Prolonged scratching can cause the skin to thicken and crack. If pain, heat, yellow crusts, clustered blisters, fever, or fatigue occur, which are different from usual symptoms, the possibility of infection or pompholyx-like eczema is promptly evaluated.
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Neurodermatitis
Representative symptoms of neurodermatitis include intense recurring itching in one or two areas and thick, rough skin resulting from continuous scratching or rubbing of those areas. It is common on the back of the neck, scalp, arms, legs, ankles, and groin; skin lines may become prominent and the color may differ from the surrounding area. Itching fluctuates but often worsens during rest or before falling asleep, which can disrupt sleep. Repeated scratching creates abrasions and hemorrhagic wounds; if oozing, pus, pain, or heat occur, infection is suspected.
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Contact Dermatitis
Contact dermatitis is a type of dermatitis where the area that touched a substance becomes red, itchy, or stinging, or develops swelling, blisters, oozing, or cracking. Irritant contact dermatitis, caused by substances that directly damage the skin such as detergents or disinfectants, tends to sting immediately after exposure. Allergic contact dermatitis, caused by metals, fragrances, or cosmetics, may appear as itching several hours to several days later. Identifying and avoiding the causative substance is the starting point of treatment.
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Nummular Eczema
Nummular eczema is a type of dermatitis where small spots or bumps cluster together to form round or oval patches that look like coins. It is common on the arms and legs, can spread to the torso, and is usually very itchy. In the early stages, the skin may swell, develop small blisters, and ooze fluid; over time, it becomes dry, leading to scabs, cracking, and scaling. If the center clears, it may look like a ring and resemble tinea (ringworm), so a diagnosis is not made based on shape alone. Prompt medical evaluation is required if there is a sudden increase in oozing, yellow crusts, heat, swelling, pain, fever, chills, or a general worsening of physical condition, as these may indicate infection.
View condition guide →Deep blisters · Peeling · Cracking
Stages of Dyshidrotic Eczema: Hands, Feet, and Recurrence
We categorize the stages from deep blisters appearing on the sides of fingers, palms, and soles, to the chronic recurrence stage where the skin dries, peels, and cracks.
Chronic Recurrent Dyshidrotic Eczema
Chronic recurrent dyshidrotic eczema involves a repeating and sometimes overlapping cycle: an active phase where small blisters appear, a phase where they burst or dry out, and a recovery phase where the skin peels in circles and cracks. Since a single photo can be confused with hand eczema or athlete's foot, you must continuously record the sensations felt before blisters appear, the number of new blisters per day, and the date when peeling and cracking end to identify the recurrence cycle.
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Dyshidrotic Eczema of the Feet
Dyshidrotic eczema of the feet is characterized by clusters of deep, small blisters on the soles and sides of the toes, accompanied by itching or tingling. It may worsen with closed-toe shoes and sweat, although sweat alone is rarely the sole cause. It must be distinguished from athlete's foot (which involves maceration between toes, fine scaling, and nail changes), palmoplantar psoriasis (which presents as thick, well-defined plaques), and contact dermatitis (which follows the shape of the shoe material).
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Dyshidrotic Eczema of the Hands
Dyshidrotic eczema of the hands is characterized by clusters of small, deep blisters felt beneath the skin on the sides of the fingers and palms, accompanied by severe itching or tingling. As blisters dry, the skin may peel in circular borders and crack. It must be distinguished from hand eczema (centered on dry cracks on the back of the hand), tinea manuum (fine scaling on one hand accompanied by athlete's foot), and contact dermatitis (overlapping with the boundaries of specific gloves or detergents).
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Dyshidrotic Eczema
Dyshidrotic eczema is a type of eczema characterized by clusters of small, deep blisters on the palms, sides of the fingers, soles, and toes, which are often very itchy or burning. Itching or tingling may start before the blisters appear, and as the blisters dry over 3 to 4 weeks, the skin may peel, become dry, and develop deep cracks. However, not all blisters on the hands and feet are dyshidrotic eczema; if they appear for the first time, are distinct on only one side, or spread to other areas, they must be distinguished from contact dermatitis, athlete's foot, or infections at a dermatology clinic. If there are yellow crusts, pus, rapidly spreading redness with heat and pain, or a fever, prompt medical evaluation is required before attempting self-care.
View Condition Guide →Wheals · Migration · Triggering stimuli
Urticaria and Irritant Wheals
We check whether the wheals fade within a few hours, whether they appear after stimuli such as heat, cold air, or friction, and whether they recur for 6 weeks or more.
Urticaria (Hives)
The representative symptom of urticaria is the sudden appearance of itchy wheals. These may appear as round bumps, broad plates, or linear shapes and can merge together; depending on skin tone, they may look red, pink, or similar to the surrounding skin color. A single wheal usually disappears within a day, but new skin changes appear in other locations, making the rash feel as if it is moving. In addition to itching, it may sting or burn, and angioedema, swelling of deeper skin layers such as the eyelids, lips, hands, or feet, may accompany it. Swelling of the face, mouth, tongue, or throat, difficulty breathing or swallowing, dizziness, or a feeling of fainting require immediate emergency assistance.
View Condition Guide →Chronic Urticaria
Chronic urticaria is a condition where very itchy bumps or raised plates recur daily or on most days for 6 weeks or longer. A single wheal usually disappears within 24 hours, but new ones may appear in other areas, changing in shape and location. Depending on skin tone, they may appear pink or red, or they may be difficult to see if they are similar to the surrounding skin color. Angioedema, which is deep skin swelling, may accompany the eyelids, lips, hands, or feet. Swelling of the face, mouth, tongue, or throat, throat tightness, difficulty swallowing or breathing, dizziness, or a feeling of fainting may indicate anaphylaxis and require immediate emergency assistance.
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Cholinergic Urticaria
Cholinergic urticaria commonly presents as multiple small wheals of about 1 to 4 mm that appear within minutes after body temperature rises and sweating occurs due to exercise, hot environments, hot showers, spicy foods, or stress. The wheals can be itchy, burning, or stinging, and may start on the torso and neck before spreading to the limbs and face. They usually subside quickly once the trigger is removed, but in rare cases, swelling of the lips or tongue, wheezing, difficulty breathing, dizziness, fainting, abdominal pain, or diarrhea may occur. If there are changes in breathing or consciousness, do not wait for it to resolve as a simple skin symptom; seek immediate emergency evaluation.
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Dermatographism
Dermatographism is a symptom where raised red lines or wheals appear along the path where the skin was lightly scratched or rubbed by a collar, towel, or bedding. It is accompanied by swelling and itching, appearing within minutes of stimulation and usually subsiding within 30 minutes. In symptomatic types, it can occur even with light pressure, and itching may worsen in the evening or at night, affecting sleep and fatigue. Rarely, the reaction may be delayed and last for several hours. If wheals appear throughout the body regardless of stimulation, or if swelling of the lips, tongue, or throat, difficulty breathing, or a feeling of fainting occur, it is not viewed as solely dermatographism.
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Cold Urticaria
Cold urticaria causes itchy, red, or dark-toned wheals, tingling, burning sensations, and deep edema after exposure to cold air, cold water, or cold objects. Holding cold objects can cause fingers to swell, and cold drinks may cause angioedema of the lips, tongue, and throat. Extensive cold exposure, especially after swimming in cold water, may lead to generalized wheals, difficulty breathing, wheezing, abdominal symptoms, palpitations, hypotension, dizziness, or fainting. Wheals may become more pronounced when the skin warms up after the cold stimulus ends.
View condition guide →Scaly plaques · Scalp · Skin folds · Nails
Psoriasis and Scaly Lesions by Area
Plaque psoriasis and involvement of the scalp, skin folds, guttate type, palms/soles, and nails are categorized by distribution, surface characteristics, and joint symptoms.
Psoriasis
Common symptoms of psoriasis include thick, raised inflammatory plaques and silvery-white scales on the scalp, elbows, knees, torso, palms, and soles. The skin may feel itchy, burning, tingling, or tight, and may crack due to dryness and bleed. Depending on the type, it may appear as small drop-shaped skin changes, smooth rashes in skin folds, pustular skin changes on the hands and feet, or severe redness and scaling across the entire body. It may be accompanied by small pits, thickening, or crumbling of the fingernails and toenails, as well as joint pain, swelling, morning stiffness, and heel pain. Seek prompt medical evaluation if the entire body suddenly turns red, or if pustular skin changes occur along with fever or a general decline in health.
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Scalp Psoriasis
Scalp psoriasis is a type of psoriasis characterized by recurring red plaques with distinct borders and thick silvery-white scales inside the scalp or outside the hairline. It is distinguished from seborrheic dermatitis, which presents with greasy, thin dandruff on the scalp, eyebrows, and sides of the nose, and tinea capitis, which can cause broken hair or localized hair loss. Changes in the elbows, knees, and nails, as well as joint pain, are also checked.
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Guttate Psoriasis
Guttate psoriasis is a type of psoriasis where multiple small pink or red scaly papules suddenly appear on the torso and limbs rather than large plaques. It may begin after an infection such as a sore throat and can resemble pityriasis rosea, drug eruptions, or tinea. Large primary plaques, medications being taken, ring-shaped active edges, existing psoriasis, and family history are also checked.
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Palmoplantar and Nail Psoriasis
Palmoplantar psoriasis appears as well-defined thick keratin plates and cracks in pressure areas of the palms and soles, while nail psoriasis may appear as small pits, yellowish-brown oil-drop spots, lifting, or crumbling. It is distinguished from the deep blisters of dyshidrosis, tinea of a single hand or foot, and nail fungus; pain, swelling, and morning stiffness in the finger and toe joints are also checked.
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Inverse Psoriasis
Inverse psoriasis is a type of psoriasis where well-defined, smooth red plaques form in moist skin folds such as the armpits, groin, under the breasts, and between the buttocks. Due to moisture, silvery-white scales are mostly absent, which can lead to confusion with candidiasis, tinea, or friction dermatitis. Surrounding satellite pustules, ringed edges, odor, and oozing are checked along with psoriasis in other areas and nail changes.
View condition guide →Itching · scratch marks · worsening at night
Chronic Itching with Pruritus and Few Lesions
We distinguish between systemic or localized pruritus (itching), where the itching itself is the primary concern rather than distinct primary skin lesions, and itching during pregnancy, while simultaneously evaluating the underlying causes.
Localized Pruritus
Localized pruritus is a condition where itching occurs repeatedly within a specific area, such as one side of the back, an arm, or the scalp, rather than across the entire body. We first examine for contact dermatitis, tinea, post-herpetic changes, and the itch-lichenification cycle; if pain, numbness, or burning sensations occur in the same area without a distinct rash, we also check for neuropathic itch. It is easier to narrow down the cause if you record the initial appearance of the symptoms before the skin thickens from continuous scratching.
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Senile and Xerotic Pruritus
Senile and xerotic pruritus is a condition where the skin thins with age and the ability to retain moisture and sebum decreases, leaving the calves, arms, and back rough and itchy. Hot baths, strong soaps, and dry heating can worsen the condition, but new medications and liver, kidney, thyroid, diabetes, or blood disorders must also be checked. Rather than repeating moisturizing alone, the distribution of itching, quality of night sleep, skin wounds, and systemic changes are examined.
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Chronic Pruritus
Chronic pruritus is a condition where itching persists for 6 weeks or more; rather than the initial rash, only lines, scabs, or color changes caused by scratching may be visible. Since causes can include not only skin issues like dryness, eczema, or scabies, but also new medications, liver, kidney, thyroid, diabetes, blood disorders, and neurological problems, we first organize the systemic distribution, medical history, and necessary tests. For itching that persists even after the cause is addressed, we perform a pattern identification (Byeonjeung) focusing on body heat, dryness, sleep, digestion, and fatigue.
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Pruritus in Pregnancy
Itching during pregnancy can occur due to stretching skin or rashes such as eczema or PUPPP; however, if there is severe itching at night without a rash, including on the palms and soles, Intrahepatic Cholestasis of Pregnancy (ICP) must be checked. Red papules or urticarial plaques starting near stretch marks on the abdomen and spreading to the thighs and buttocks are clues for PUPPP. If there is severe itching, jaundice, dark urine, or decreased fetal movement, contact your obstetrician immediately.
View condition guide →Flushing · blood vessels · dandruff · hair follicles
Redness and Inflammation of the Face and Scalp
We distinguish between temporary facial flushing and persistent rosacea-related redness, emotional flushing or roughness related to Demodex mites, and scaling or follicle-centered inflammation around the scalp and nose based on location and duration.
Emotional Flushing
Emotional flushing is a symptom where the cheeks, ears, entire face, neck, and upper chest suddenly turn red, darken from the usual skin tone, or feel hot in situations where one is the center of attention, such as during presentations, conversations, embarrassment, or conflict. It may be accompanied by sweating, palpitations, trembling, or nausea; the moment one notices the face turning red, thoughts may stop, or one may avoid eye contact and wish to leave the situation. Unlike temporary flushing that subsides after the situation ends, if the color lingers and there are visible blood vessels, papules, stinging, or eye irritation, we differentiate it from skin diseases such as rosacea. If one avoids presentations, meals, or meetings due to concern over flushing, this functional impairment is also a significant symptom.
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Folliculitis
Folliculitis typically presents as clusters of small red pimples or pus-filled pustules that appear suddenly around the hair follicles. The area around the skin change may be red, itchy, or burning, and may be painful when pressed; scabs may form after pustules burst. Superficial folliculitis remains as small papules or pustules, but if it deepens, it may appear as large, hard, painful boils or a carbuncle (connected boils), increasing the risk of scarring and hair loss. If redness and pain suddenly spread or are accompanied by fever, chills, or body aches, the spreading infection is promptly evaluated.
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Demodex Mites
Demodex mites normally live in the facial and eyelash follicles of many adults, so the mere fact that they are visible or detected does not necessarily mean they are causing symptoms. If they increase excessively and lead to demodicosis, symptoms such as facial itching, burning sensation, sensitivity, erythema, sand-like rough skin with follicular scaling, papules, and pustules may appear. If the eyelids are affected, itching, irritation, scaling, thickening, loss of eyelashes, or conjunctival irritation may occur. However, as these are similar to rosacea, eczema, acne, or other types of blepharitis, do not self-diagnose without a dermatology or ophthalmology examination.
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Facial Flushing
Facial flushing is a symptom where the skin suddenly becomes red, hot, or burning due to increased blood flow in the face, neck, and upper chest. It may appear briefly and disappear after emotional stress, exercise, fever, temperature changes, spicy food, or alcohol consumption. Rosacea is characterized by more frequent flushing centered on the cheeks, nose, forehead, and chin, accompanied by persistent color changes (red, purple, or brown), visible capillaries, stinging, pain, and papules. Bloodshot eyes, dryness, foreign body sensation, and eyelid swelling may also occur. Swelling of the lips or tongue, difficulty breathing, eye pain, photosensitivity, changes in vision, sudden facial drooping, arm weakness, or slurred speech must be evaluated immediately.
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Rhinophyma
Rhinophyma may begin with the face repeatedly becoming red or darkening to a purple or brown tone compared to the skin tone, centered on the nose, cheeks, forehead, and chin, with the color persisting over time. It may be accompanied by burning, stinging, sensitivity, visible fine blood vessels, and acne-like papules, pustules, or edema. In some cases, the skin of the nose, forehead, and chin thickens. Dryness, foreign body sensation, redness, and eyelid swelling in the eyes may appear before skin symptoms; severe eye pain, light sensitivity, or changes in vision require prompt ophthalmology evaluation.
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Seborrheic Dermatitis
Seborrheic dermatitis is a type of dermatitis characterized by white or yellow greasy, adhering scales and dandruff in areas with high sebum production, such as the scalp, hairline, eyebrows, eyelids, nasolabial folds, around the ears, and the chest. The skin may appear red, pink, purple, or lighter than the surrounding area, and may be itchy, stinging, or irritated. It varies from mild forms appearing only as scalp dandruff to patterns that spread like plaques across various parts of the face and body, often recurring in cycles of improvement and worsening. If there is oozing, pus, thick crusts, severe pain, redness, rapid spreading, eye pain, or changes in vision, do not dismiss it as a simple recurrence and seek medical evaluation.
View Condition Guide →Rough surface · Flat papules · Central depression
Warts, Molluscum Contagiosum, and Viral Papules
Small raised lesions, such as common warts, flat warts, and molluscum contagiosum, are distinguished by their surface, central shape, location, and pattern of spread.
Molluscum Contagiosum
Molluscum contagiosum typically presents as small, firm, pearly bumps on the skin with a characteristic navel-like depression in the center and a visible white core. They are generally painless, but may become red, swollen, or itchy if scratched or if inflammation occurs. People with weakened immunity may develop larger or more numerous bumps. If they appear on the genitals or around the eyes, or are accompanied by severe redness, pain, pus, or fever, do not wait and seek medical evaluation immediately.
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Warts
Warts are firm or rough bumps that develop slowly on the skin; they vary in shape and can be round, flat, smooth, or look like cauliflower or threads. Some have small black dots that look like seeds, which are actually blood vessels. Plantar warts grow under thick calluses and can feel like stepping on a needle or pebble while walking. Most are not itchy or painful, but pain, itching, burning, or bleeding may occur. If they grow rapidly, look like open sores, show repeated bleeding or changes in shape, or appear on the face or genitals, do not attempt self-treatment and seek medical evaluation.
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Flat warts
Flat warts are smaller than common warts and appear as smooth, flat, round bumps, often appearing in clusters rather than individually. They can appear skin-colored, pink, brown, or purple and are common on the face. In children, they are often seen on the cheeks and forehead; in adults, they are noticeable in areas where hair is removed, such as the neck, legs, or beard area. Most are not painful or itchy, but if pain, itching, burning, or bleeding occurs, or if the shape changes rapidly, seek a dermatological examination.
View condition guide →Scaling · Ring shape · Herald patch
Differential Diagnosis of Ring-shaped, Spotted, and Scaly Rashes
Scaly rashes that spread across the torso, such as pityriasis rosea and tinea, are compared with nummular eczema and psoriasis.
Tinea
Tinea is a condition caused by dermatophytes invading the skin, scalp, feet, groin, or nails. On the skin, it commonly presents as itchy circular or ring-shaped rashes with more prominent, scaly edges. Depending on skin tone, it may appear red or darker, such as brown or gray, and may not form a typical ring on the face, neck, or scalp. It can cause scaling, broken hair, or partial hair loss on the scalp; white, soggy, or cracked skin between the toes; itchy bordered rashes in the groin; and thickening, discoloration, or brittleness of the nails. As it resembles other skin conditions, do not confirm a diagnosis based on appearance alone; seek medical evaluation if it spreads rapidly or is accompanied by pain, pus, or fever.
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Pityriasis Rosea
Pityriasis rosea typically begins with a large, oval 'herald patch' with scaly edges on the chest, abdomen, or back, followed by the spread of smaller oval patches to the torso and limbs. On the back, these may align along skin folds in a pattern resembling a Christmas tree. Depending on skin tone, the patches may appear pink, red, purple, gray, or brown, and itching may be absent or severe. If you experience new rashes during pregnancy, painful blisters, mucosal skin changes, fever, difficulty breathing, or rapid worsening, you should seek prompt medical evaluation to rule out other causes.
View disease information →Images are examples provided to help understand how the condition may appear. The sources and terms of use for actual clinical photographs can be found on each disease page; diagnosis is not made based on photographs alone.