What it looks like: Medically known as atopic dermatitis, eczema is an umbrella term for a range of skin conditions characterized by red, splotchy, flaky, dry, cracked, or crusty skin that can emit clear fluid when scratched. It’s usually clustered around the insides of elbows and knees, but can appear anywhere on the skin.
Other symptoms to note: Eczema is usually itchy and most common in young people, although many adults also have eczema-prone skin. Cold, dry weather and overexposure to water can exacerbate the condition, according to Dr Zeichner.
2) Contact Dermatitis
What it looks like: Contact dermatitis has the same symptoms mentioned above, and can be a red rash that appears scaly or blistered, depending on its cause and severity. This rash often has a distinct border.
Other symptoms to note: Contact dermatitis appears following exposure to an irritant or allergen, and it’s the most common rash caused by external factors, Dr Zeichner says. (This can include certain chemicals, acids, botanicals, metals, and more.) Allergens usually cause a shiny, blistered, itchy rash, while irritants tend to cause a dry, scaly, less itchy rash. It can appear hours to days after exposure.
What it looks like: Ringworm is a common skin infection caused by a fungus. It gets its name from its circular rash, which is often red, swollen, and cracked.
Other symptoms to note: This rash is itchy and can cause hair loss when it occurs on the scalp. The same fungus also causes athlete’s foot and jock itch. Ringworm is contagious, so avoid touching people and pets or sharing objects like towels with others during flareups.
What it looks like: Rosacea causes redness and thick skin on the face, usually clustered in the center. Easy flushing, a stinging sensation, and small, pus-filled pimples are other common signs of the condition, which is often confused with acne breakouts.
Other symptoms to note: With rosacea, skin might feel rough, bumpy, or warm to the touch. Redness usually appears on the forehead, nose, cheeks, and chin. Red, itchy, sensitive eyes are also associated with the condition. Triggers include “spicy food, hot beverages, alcohol, extremes in temperature, and physical and emotional stress,” Dr Zeichner explains.
What it looks like: Psoriasis causes patches of thickened skin, most often with silver, scaly flakes. It’s usually found around the elbows, feet, knees, palms, and scalp.
Other symptoms to note: Telltale scales set psoriasis apart from other rashes. Up to 20% of people with psoriasis also experience psoriatic arthritis. Psoriasis is not contagious; it’s due to “overactivity of the immune system resulting in skin inflammation,” Dr Zeichner explains.
Right image credit: Tim Kubacki
What it looks like: Also called urticaria, hives are raised welts in the skin that appear red or discolored. They range in size from small bumps to larger patches.
Other symptoms to note: Hives are most of often the result of exposure to allergens, and they could be a sign of a serious allergic reaction. Hives might not cause any discoloration on darker skin, so be alert for raised patches or welts—those could be a sign of urticaria.
What it looks like: Acne causes red, discolored bumps on the skin, along with whiteheads, blackheads, and cysts.
Other symptoms to note: Acne is one of the most common skin conditions Dr Zeichner says, so you likely have experience with pimples already. The causes vary, but are often rooted in excess oil and bacteria on the face, chest, or back, which can be triggered by hormonal issues, stress, certain foods, and irritating products.
What it looks like: Also known as herpes zoster, shingles is a blistering rash. It often appears in a stripe or in the top quadrant of the head, but only on one side of the body.
Other symptoms to note: Blisters are painful and are sometimes accompanied by fever, headache, and chills. Local tingling or pain is common before the blisters appear. Shingles can affect the eye and even cause vision loss. The condition is caused by the same virus as chickenpox.
Bottom image credit: Preston Hunt
9) Seborrheic Dermatitis
What it looks like: Seborrheic dermatitis is a form of eczema that is characterized by scaly, oily or greasy patches of skin, usually on the scalp.
Other symptoms to note: This condition is itchy and can cause dandruff and buildup on the scalp. It’s also common on other oily areas, like the face and chest, and can be difficult to treat. Dr Zeichner explains that although the exact cause of seborrheic dermatitis is unknown, the body overreacts to yeast on oily parts of the skin, causing the thick, flaky buildup.
Top image credit: Amras666
10) Perioral Dermatitis
What it looks like: Like seborrheic dermatitis, perioral dermatitis causes red, inflamed skin and small pustules around the nose and mouth.
Other symptoms to note: Flareups can be itchy and uncomfortable, and are often confused with acne. There is no known cause of perioral dermatitis, but overuse of topical corticosteroids is associated with the condition.
What it looks like: Scabies is a discolored, splotchy rash that can appear pimple-like on any affected parts of the skin. Patients might also notice tiny lines on the skin where the mites have burrowed.
Other symptoms to note: Scabies is very itchy, and usually more intense at night. Unlike the other rashes on this list, this one is caused by an infestation of mites. It’s very contagious and spreads easily through skin-to-skin contact in crowded spaces.
Top image credit: Cixia
Bottom image credit: Tim Kubacki
12) Drug Rash
What it looks like: Drug rashes are usually speckled, itchy, and red, and can cover large areas of skin. They can appear days to weeks after taking a medication.
Other symptoms to note: Drug rashes can be a side effect of or a reaction to a new medication; almost any medication can cause a drug rash, but antibiotics and nonsteroidal anti-inflammatory drugsare the most common culprits. The rash might not be anything to worry about, but it could be a sign of a serious allergic reaction, especially if combined with difficulty breathing. Contact your doctor immediately if you experience these symptoms.
13) Lichen Planus
What it looks like: Purplish legions on the inner arms, legs, wrists, or ankles can signify lichen planus, a skin rash triggered by an overreaction of the immune system.
Other symptoms to note: The legions are usually itchy and may cause skin discoloration as they heal. Lichen planus does not have one single cause—illnesses, allergies, and stress can all trigger breakouts. It is not contagious.
Right image credit: James Heilman, M.D.
What it looks like: Measles causes flat, red spots that cover huge swaths of skin. The rash often appears on the face near the hairline, then spreads down to the feet.
Other symptoms to note: The rash is accompanied by flu-like symptoms, including high fever, cough, and runny nose. Conjunctivitis (pink eye) is also common. Young people could face severe complications from measles, so contact your healthcare provider if you suspect exposure to the illness. Measles is spread when an infected person coughs or sneezes, and it’s one of the most contagious diseases.
Top image credit: Mike Blyth
15) Hand, Foot, and Mouth Disease
What it looks like: Hand, foot, and mouth disease is named for its characteristic flat, red spots that appear on the palms, soles of the feet, and around the mouth.
Other symptoms to note: Spots may blister over time. Cold-like symptoms, including fever and loss of appetite, might also appear. It’s usually not serious, but it’s very contagious and can spread quickly through skin contact or respiratory transmission among people of any age, especially in schools.
What it looks like: Intertrigo is a rash that causes discolored skin in hot, sweaty parts of the body. It’s a direct reaction to repeated friction and moisture.
Other symptoms to note: It’s characterized most by its symptoms, not its appearance. Raw, itchy skin in places like the armpits, genitals, or beneath the breasts could likely be intertrigo—especially if it has a foul odour.
17) Tick Bite
What it looks like: The most recognisable reaction on this list is the bullseye rash—a large, red, target-like rash that signals the early stages of Lyme disease from the bite of an infected tick. While the Australian government says there is little evidence Lyme disease occurs in Australia, there are increasing incidences of local diagnoses. Most tick bites do not cause a bullseye rash, but it appears in about 70 to 80% of Lyme patients.
Other symptoms to note: You might actually find a tick attached to you before a rash appears, which is usually itchy. The bullseye rash in particular is a telltale sign of Lyme disease, even though some patients never get one, so monitor your symptoms and let your doctor know as soon as you notice one.
What it looks like: Lupus, a chronic autoimmune disease that causes inflammation throughout the body, often presents with a red, butterfly-shaped rash across the cheeks and nose. It is usually worsened by exposure to the sun.
Other symptoms to note: Although the rash does not leave scarring, it could cause discoloration after it disappears. The butterfly rash is distinct from the sores and scaly lesions also caused by lupus. Each case varies, but topical treatments and lifestyle changes can help the rash fade.