An itch that will not go away, a new white patch, or a rash that lingers may look like a skin-deep concern. It can also signal infection, immune dysfunction, metabolic problems, or even cancer.
At a recent EFC Arcadia community health lecture, USC Keck School of Medicine dermatology professor Fu-Tong Liu, M.D., Ph.D., said the skin is the body’s largest organ and a window into internal health.
In “Dermatology: More Than Skin Deep,” he stressed that early detection and timely care can keep disease from worsening.
Liu noted that dermatology extends far beyond acne, athlete’s foot, eczema, and hives to include infections, tumors, chronic inflammation, genetic conditions, and autoimmune disease.
Skin, he emphasized, is more than appearance; it is often the body’s first warning sign.
Shingles Strikes | Act Fast
Liu described shingles as one of the most commonly delayed conditions. The virus that causes chickenpox can remain dormant for years, then reactivate.
It often begins with pain, burning, or tingling on one side of the body, followed days later by clusters of blisters along a nerve pathway.
A rash near the eye can threaten vision, and pain can persist long after the rash fades. Liu advised seeking care promptly if shingles is suspected so a physician can assess antiviral treatment.
Adults 50 and older can also discuss the two-dose recombinant shingles vaccine with their doctor.
Rashes Return | Find Causes
Liu explained that atopic dermatitis, commonly called eczema, often causes dry, red, intensely itchy skin that flares repeatedly. Psoriasis, he noted, is a chronic inflammatory disease linked to immune dysfunction; it is not contagious.
Neither should be managed simply by enduring symptoms or repeatedly using medication without medical guidance.
Consistent moisturizing, fragrance-free products, and avoiding excessive scratching are the basics, Liu said. If a rash spreads, disrupts sleep, or keeps returning, a dermatologist should assess treatment options.
Hives can be just as frustrating. Liu noted that acute episodes may be linked to food, medication, viral illness, or environmental triggers. When welts recur for more than six weeks, chronic hives—and sometimes an autoimmune driver—should be considered.
Rather than guessing, he advised tracking timing, foods, medications, illnesses, and environmental changes. Swelling of the lips or tongue, wheezing, or trouble breathing requires emergency care.
Spots Change | Seek Care
The best defense against skin cancer, Liu stressed, is early detection. He recommended the ABCDE guide for moles and dark spots: Asymmetry, irregular Borders, uneven Color, increasing Diameter, and Evolving change.
Any new spot, or a mole that grows, changes color, bleeds, crusts, or itches, deserves prompt medical attention. Liu also reminded listeners that melanoma can appear on the palms, soles, and beneath the nails—not only on sun-exposed skin.
Skin changes accompanied by whole-body symptoms should never be dismissed as a simple allergy, Liu cautioned.
Lupus can affect the skin, joints, kidneys, and brain. Dermatomyositis and scleroderma may also first reveal themselves through the skin.
Liu further warned that serious drug reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, can cause widespread rash, blisters, skin peeling, and sores in the mouth, eyes, or genitals.
If these symptoms come with fever, trouble swallowing, or breathing problems, he said, do not wait—go to the emergency room.
For Liu, healthy skin does not depend on costly products.