Common Skin Issues in Mount Pleasant and How to Treat Them
Ashley Harwyn, PA-C, ABAAHP | Published August 4, 2025 | Last updated October 6, 2026 | 20 min read
Heat, sweat, and strong sun shape a familiar set of skin problems here. This guide names each one, what helps first, and when a spot belongs with a dermatologist.
The AAD's sunscreen advice comes down to broad-spectrum SPF 30 or higher, enough of it, and reapplying outdoors.
In Mount Pleasant and Charleston, the skin problems most tied to heat, sweat, and strong sun are sun damage, melasma, breakouts, rosacea flares, heat rash, and a fungal rash called tinea versicolor.[3][5][7][8][9] Each has a first step in the guidance cited below, and a spot that is new or changing belongs with a board-certified dermatologist before anything cosmetic.[10]
By NOAA's climate normals, Charleston summers are hot, and the EPA's UV Index sets out when sun protection is needed.[1][2] This guide walks through each of the common local concerns: what it usually looks like, why heat and sun make it worse, what helps first, and the signs that mean you should skip the skin care aisle and book a medical exam. For the overview of how we approach skin at our offices, see our medical skin care page.
Key takeaways
Charleston's normal daily high in July is 87.5 degrees Fahrenheit, and the normal July low is 77.1.[1]
The EPA says a UV Index of 3 or more calls for sun protection, and its shadow rule is simple: if your shadow is shorter than you, seek shade.[2]
In a long Australian trial, adults assigned to daily sunscreen had 11 new melanomas over the follow-up, against 22 in the group that used it when they chose.[4]
Sunlight triggers melasma, and visible light can worsen it too, which is why dermatologists suggest a tinted sunscreen with iron oxide.[5]
Heat rash comes from heavy sweating in hot, humid weather, while tinea versicolor is a common fungal rash that typically occurs in warm, humid climates and can come back in warm weather.[8][9]
A spot that is new, different from your others, or changing, itching, or bleeding needs a board-certified dermatologist first.[10]
Section 01 / Heat and UV by the numbers
Why does the Lowcountry climate show up on your skin?
Start with the numbers. NOAA's 1991 to 2020 climate normals for Charleston put the normal daily high at 87.5 degrees Fahrenheit in July and 86.4 in August.[1] The normal daily low in July is 77.1 degrees.[1] Even January has a normal high of 58.0.[1] In midsummer, the normal overnight low stays in the upper 70s.
Heat is half of it. Sun is the other half. The EPA's UV Index runs from low (1 to 2) to moderate and high (3 to 7) to very high and extreme (8 and above).[2] At 3 or higher, the agency says protection is needed, including shade from late morning through mid-afternoon, a broad-spectrum sunscreen, protective clothing, a wide-brimmed hat, and sunglasses.[2] You do not need an app to judge it. The EPA's shadow rule says that when your shadow is shorter than you are, around midday, you are getting higher UV exposure.[2]
Each of the skin problems below has a link to sun, heat, or sweat in the sources cited. Some are about sun over years (sun spots, wrinkling, skin cancer risk). Some are about sun over weeks (melasma darkening). Some are about sweat and heat right now (breakouts, heat rash, fungal patches, rosacea flushing). The table below sorts them so you can see which one you are dealing with.
Source: Green AC et al., Journal of Clinical Oncology, 2011. Sunscreen was applied to the head and arms during the 1992 to 1996 trial.
Antifungal treatment, such as a selenium sulfide or ketoconazole wash[9]
You are not sure it is fungal, or it keeps returning[9]
Before your skin visit
What to mention about your summer skin
Tap each one that fits you. This is not a diagnosis. It flags what is worth raising so your visit starts in the right place.
Section 02 / Sun over the years
Sun damage: what years of Lowcountry sun do, and what prevents it
Sun damage is slow. The American Academy of Dermatology (AAD) links too much unprotected UV exposure to premature skin aging, such as wrinkles and age spots, and to skin cancer, which it estimates one in five Americans will develop in their lifetime.[3] For prevention, the AAD's sunscreen guidance centers on choosing the right product and applying it correctly.[3]
The AAD recommends a broad-spectrum sunscreen with SPF 30 or higher that is water resistant.[3] SPF 30 blocks 97% of the sun's UVB rays, and higher numbers block only slightly more.[3] A higher SPF also does not last longer on your skin, so the reapplication rule stays the same: about every two hours outdoors, and after swimming or sweating.[3] Clouds do not get you off the hook either, since up to 80% of the sun's harmful UV rays can pass through them.[3]
Amount is where most people fall short. Most adults need about one ounce, roughly a shot glass, to cover the skin clothing leaves bare.[3] The AAD notes that many people apply only 20 to 50% of the amount needed to reach the SPF on the label.[3] And no sunscreen is truly waterproof or sweatproof. Makers are not allowed to use those words, because they would be misleading.[3] For a day on the water or at the beach, that points to a water-resistant product reapplied about every two hours, plus the shade and hat the EPA lists.[2][3]
Does daily sunscreen really change outcomes, or only sunburns? One of the best tests of that question is a randomized trial in Nambour, a township in Queensland, Australia. In 1992, 1,621 adults aged 25 to 75 were assigned to daily sunscreen on the head and arms or to use it at their own discretion, through 1996.[4] Ten years after the trial ended, the daily group had 11 new primary melanomas and the comparison group had 22.[4] For invasive melanomas, the count was 3 versus 11.[4]
Read that result with care. The overall melanoma difference sat right at the edge of statistical significance, and the numbers of cancers were small.[4] The authors' own conclusion was measured: melanoma “may be preventable” by regular sunscreen use in adults.[4]
If you already have sun spots, they can be treated, but naming the spot comes first. Our guide to laser resurfacing for dark spots explains how to tell a sun spot from melasma and from a spot that needs a dermatologist, and our laser services page lists the treatments we offer and their downtime.
Section 03 / Pigment that answers to light
Is it melasma, and why does summer make it darker?
Melasma causes darker spots and patches when the cells that make skin pigment become more active. The AAD lists sun exposure, pregnancy, stress, a medical condition, and some medicines, such as birth control pills, as possible causes, and notes it may be more noticeable on darker skin.[5] It can fade on its own, but for some people it lasts for years.[5]
The AAD is direct about light: sunlight triggers melasma, so protection has to be daily, including cloudy days and after swimming or sweating.[5] Its sunscreen advice for melasma is broad-spectrum, water resistant, SPF 30 or more, put on 15 minutes before going out and reapplied at least every two hours.[5]
UV is not the whole story. Visible light has been shown to worsen melasma, especially in people with darker skin tones, so the AAD suggests a tinted sunscreen containing iron oxide in addition to SPF 30 or higher.[5] Tanning beds and sunlamps are out entirely, because indoor tanning can worsen melasma and stop treatment from working.[5] A wide-brimmed hat and shade do real work here too.[5]
Two quieter habits matter. Choose gentle, fragrance-free products, because a product that burns or stings is irritating your skin, and that irritation may darken the spots.[5] And give treatment time, since melasma fades slowly. If it does not go away with good sun care, the AAD's advice is to see a board-certified dermatologist about prescription medicines or in-office procedures.[5]
Irritation can darken melasma.[5] Our guide to laser treatment for melasma and dark marks explains why it treats a laser as rarely the right first move for melasma, and our hyperpigmentation page covers how we sort the different kinds of dark spots at a visit.
Not sure whether it is melasma, a sun spot, or something else? Call 843-981-0870. Ask about a skin visit. A spot that is new, changing, itching, or bleeding belongs with a board-certified dermatologist before any treatment.
Section 04 / Sweat and breakouts
Why do breakouts flare when it is hot and sticky?
Summer brings more sweat, more sunscreen, and more time outdoors, and each of those touches how acne behaves. The AAD's at-home acne advice speaks to exactly those habits: washing after sweating, choosing sunscreen that will not clog pores, and keeping oily hair off the face.[6]
Wash gently, up to twice a day and after sweating, with a mild, non-abrasive cleanser and your fingertips, because washcloths, sponges, and scrubbing tools can irritate your skin.[6] Use gentle, alcohol-free products, and skip astringents, toners, and exfoliants, which can dry the skin and make acne look worse.[6] If you have oily hair, shampoo more often and keep it off your face, since oil from hair can cause breakouts on the forehead.[6]
Sunscreen and acne are not enemies. The AAD recommends broad-spectrum, water-resistant SPF 30 or higher when outdoors, and suggests looking for a label that says “non-comedogenic” or “won't clog pores.”[6] Sun matters for acne in two ways: tanning damages skin and can worsen acne, and some acne medicines make your skin much more sensitive to UV.[6]
Hands off is the hardest rule. Picking, popping, or squeezing makes acne take longer to clear and raises the risk of scars and of the dark marks called post-inflammatory hyperpigmentation.[6] Patience matters as well, because a new treatment may take several weeks to a few months to show a difference, and switching too often can irritate your skin and cause more breakouts.[6]
If you keep seeing breakouts after following these tips, the AAD's advice is to partner with a board-certified dermatologist.[6] Our acne treatment page explains the options we use, from prescription washes and retinoids to oral medicines, and when we refer for isotretinoin. If scars are already the bigger concern, our acne and acne scars page covers that separately.
A summer skin plan that holds up
Name the problem first, then match the care: daily broad-spectrum SPF 30 or higher, a tinted iron oxide sunscreen for melasma, a gentle wash after sweating, trigger tracking for rosacea, and cooling and drying for heat rash.
Where summer skin care goes wrong
Treating every bump as acne, using acne products on rosacea, layering heavy creams on heat rash, skipping sunscreen on cloudy days, or fading a new or changing spot before anyone has examined it.
Section 05 / Redness and triggers
Rosacea or just a hot face? Calming redness in a hot climate
Everyone turns pink after a run in August. Rosacea is different. It is a long-term skin condition that makes the face red, and MedlinePlus lists easy blushing or flushing, spider-like blood vessels, a red nose, acne-like sores that may ooze or crust, burning or stinging, and irritated, watery eyes among its symptoms.[7] It is less common in men, but tends to be more severe when men have it.[7]
There is no known cure, so care is about control, and control starts with triggers.[7] Triggers vary from person to person, and avoiding yours may help prevent or reduce flare-ups.[7] Two of the triggers MedlinePlus names fit this climate exactly: sun exposure, and a lot of activity in hot weather.[7] Others include stress, spicy foods, alcohol, hot drinks, wind, hot baths, cold weather, some skin products, and exercise.[7]
In practice that means daily sunscreen, which MedlinePlus lists, and, since it also lists a lot of activity in hot weather as a trigger, planning hard exercise or yard work for cooler times of day.[7] MedlinePlus notes that your provider will help you identify the things that make your symptoms worse.[7] It can help to note what you ate, drank, and did in the hours before a flare, and bring those notes to your visit.
One mistake is common enough to call out. Rosacea is not acne, and it will not improve with over-the-counter acne treatment.[7] For the acne-like bumps, a clinician may suggest antibiotics applied to the skin or taken by mouth, and for severe cases that have not improved, isotretinoin is sometimes considered.[7] In very bad cases, laser treatment may help reduce the redness.[7] Our skin rejuvenation page explains how the laser we use there targets small red veins, and when it is not the first choice.
If you are not sure whether you have rosacea, acne, or something else, get a diagnosis before you buy anything, because the first steps differ.[6][7]
Section 06 / Rashes that are not acne
Heat rash and fungal patches: the summer bumps people mistake for acne
Two warm-weather rashes are easy to confuse with breakouts, and both respond to different care.
Heat rash is the simpler one. The CDC describes it as skin irritation caused by excessive sweating during hot, humid weather.[8] It looks like red clusters of pimples or small blisters, and it usually appears on the neck, upper chest, groin, under the breasts, and in elbow creases.[8] Because it comes from heavy sweating, the fix is to cool down. The CDC's advice is a cooler, less humid environment when possible, keeping the rash area dry, and powder for comfort, while avoiding ointments and creams.[8]
Tinea versicolor is a common fungal infection of the outer layer of skin, caused by a type of fungus called Malassezia that is normally found on human skin.[9] It is most common in teens and young adults, typically occurs in warm and humid climates, and does not spread from person to person.[9] The telltale sign is patches with sharp edges and fine scale on the back, underarms, upper arms, chest, and neck.[9] The patches are often lighter or darker than the skin around them. They do not darken in the sun, so they can look lighter than the healthy skin around them once you have some color.[9]
Treatment is usually straightforward. Antifungal medicine on the skin or by mouth works, and so does an over-the-counter dandruff shampoo with selenium sulfide or ketoconazole, left on the skin for 10 minutes each day in the shower.[9] The catch is color. The fungus is often easy to clear, but the color changes can last for months, and the rash can come back in warm weather.[9] For people who get it every summer, MedlinePlus suggests avoiding excess heat and sweating, and using an anti-dandruff shampoo on the skin once a month to help prevent it.[9]
MedlinePlus advises contacting a provider if you develop symptoms of tinea versicolor.[9] The same goes for any rash that does not behave the way these descriptions suggest: have it examined rather than rotating creams. For tinea versicolor, a provider may look at a skin scraping under a microscope to help confirm it.[9]
Section 07 / Knowing the line
When should you see a dermatologist instead?
Most of what this guide covers is everyday skin care and medical skin treatment. Some things are not, and the line is worth knowing before you book anything cosmetic.
A spot comes first. The AAD's advice is to see a board-certified dermatologist if you notice any new spot, a spot that looks different from the others, or one that is changing, itching, or bleeding.[10] It also teaches the ABCDE warning signs of melanoma:[10]
A, asymmetry: one half of the spot is unlike the other half.
B, border: the edge is irregular, scalloped, or poorly defined.
C, color: the color varies from one area to the next, such as shades of tan, brown, or black, or areas of white, red, or blue.
D, diameter: melanomas are usually larger than 6 millimeters, about the size of a pencil eraser, when diagnosed, though they can be smaller.
E, evolving: the spot looks different from the rest or is changing in size, shape, or color.
That exam comes before any peel, laser, or fading cream on that spot. We would rather a spot be named by the right specialist than faded on a guess. How often a full-body skin check makes sense is a separate question, and our guide on how often a skin analysis should be performed covers it, along with how a screening exam differs from a cosmetic skin analysis.
A few other situations point to a dermatologist too. Melasma that has not faded with steady sun protection is one; the AAD sends those patients to a board-certified dermatologist for prescription medicines or procedures.[5] Acne that is severe or scarring and may need isotretinoin is another; our acne treatment page describes isotretinoin as tightly regulated and says that when acne reaches that point we will help you find a dermatologist who prescribes it. Any rash you cannot name, or one that keeps coming back despite the right care, deserves a proper diagnosis.
Where does a visit with us fit? At our Mount Pleasant office on Bramson Court or at The Longevity Club on Rutledge Avenue in downtown Charleston, Ashley Harwyn, PA-C is our clinician, and our medical skin care page says a skin visit includes questions about stress, sleep, diet, and the products you use. Depending on the concern, the plan might be prescription acne care, a melasma plan built around sun protection, a facial or chemical peel for tone and texture, or a laser treatment for sun spots. That page also says that if we notice a worrying spot, we will say so plainly and help you get it checked.
For the routine you follow at home, our guide on why customized skin care matters goes through the few ingredients with real evidence and the ones you can skip.
Medical Skin Care
The map of our skin services and the daily basics that come first. Read Medical Skin Care.
Acne Treatment
For breakouts that sweat and good habits have not settled. Read Acne Treatment.
Founder, Solcara Health · Diplomate, American Board of Anti-Aging Health Practitioners (ABAAHP)
Ashley has practiced medicine for more than fifteen years. Her path into it began at home, with a family member born with a congenital heart defect and a childhood spent watching how much the quality of a clinician's attention could change the shape of a life. She has since practiced across a range of settings, including medical mission work in Uganda, before founding Solcara to build the kind of practice she kept wishing existed, one that treats patients as whole people and tells them the truth about what the evidence does and does not support.
NOAA NCEI 1991 to 2020 climate normals for Charleston, the EPA UV Index scale, American Academy of Dermatology patient guidance on sunscreen, melasma, acne, and the ABCDEs of melanoma, MedlinePlus entries on rosacea and tinea versicolor, CDC guidance on heat rash, and a randomized sunscreen trial in the Journal of Clinical Oncology, each accessed October 5, 2026.
NOAA National Centers for Environmental Information. U.S. Climate Normals 1991-2020: normal daily maximum and minimum temperature, Charleston, SC (Comparative Climatic Data tables). NOAA NCEI. 2025. ncei.noaa.gov
U.S. Environmental Protection Agency. UV Index Scale. EPA. epa.gov
American Academy of Dermatology. Sunscreen FAQs. AAD. aad.org
Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. Journal of Clinical Oncology. 2011. pubmed.ncbi.nlm.nih.gov
American Academy of Dermatology. 4 dermatologist tips to make melasma less noticeable. AAD. aad.org
American Academy of Dermatology. 6 skin care habits that can clear acne. AAD. aad.org
MedlinePlus Medical Encyclopedia. Rosacea. U.S. National Library of Medicine. 2025. medlineplus.gov
Centers for Disease Control and Prevention, NIOSH. Heat-related Illnesses. CDC. cdc.gov
MedlinePlus Medical Encyclopedia. Tinea versicolor. U.S. National Library of Medicine. 2024. medlineplus.gov
American Academy of Dermatology. What to look for: ABCDEs of melanoma. AAD. aad.org
Medical Disclaimer: This page is for educational and informational purposes only and does not constitute medical advice, and reading it does not create a patient-provider relationship. It describes general medical information and categories of care, not a recommendation that any individual start, stop, or change any test, treatment, or medication. Any diagnosis or treatment decision requires evaluation by a qualified, licensed clinician who knows your personal and family history. Consult a qualified healthcare provider before making medical decisions. Information reflects sources available as of October 5, 2026.
Ashley Harwyn, PA-C, ABAAHP, is a Diplomate of the American Board of Anti-Aging Health Practitioners (ABAAHP) through A4M and the founder of Solcara Health. Solcara serves South Carolina from Downtown Charleston (163 Rutledge Ave, Ste 202, The Longevity Club) and Mt. Pleasant (496 Bramson Ct, Ste 120).
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Ashley Harwyn, PA-C
PA-C, ABAAHP · Founder, Solcara Health
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