Conditions treated

Skin, hair, and nail conditions

Dermatology covers a very wide range of problems that often look alike and behave nothing alike. This page groups the conditions Dr. Porto treats by what they actually have in common, with in-depth guides for the ones we see most.

Reviewed by Dennis A. Porto, MD, MPH, FAAD Double board-certified in dermatology and Mohs surgery Last reviewed August 2026

In-depth guides

Each guide explains what causes the condition, which treatments have evidence behind them, and what to expect once treatment starts.

Acne Why acne forms, which prescriptions have evidence behind them, and how long each one takes to work. Rosacea Telling rosacea apart from acne, identifying your triggers, and treating flushing, bumps, and visible vessels. Eczema Getting a flare under control and keeping it that way — barrier repair, correct steroid use, and newer non-steroid options. Hair loss Working out which kind of hair loss you have before treating it, and what the evidence supports for each pattern. Melasma Why melasma returns, how to fade it without rebound, and the daily protection that decides whether treatment holds. Psoriasis Why psoriasis is an immune disease rather than a skin one, how it differs from eczema, and the full treatment range from topicals through biologics. Seborrheic dermatitis The yeast-driven cause behind dandruff and facial flaking, why moisturizer alone never fixes it, and how to keep it controlled. Perioral dermatitis Why topical steroids make this rash worse before better, what clears it, and how long the rebound period realistically lasts. Hyperpigmentation Why pigment depth decides your timeline, which topicals have evidence behind them, and why treating the cause comes first. Keratosis pilaris Why scrubbing the bumps backfires, which chemical exfoliants smooth them, and how to treat the redness separately.

More guides are added over time. Everything in the list below is treated whether or not a guide exists for it yet.

Conditions by group

Dr. Porto is a general dermatologist as well as a Mohs surgeon, so the full range of medical dermatology is covered — not only cosmetic concerns.

Acne and oil-related conditions

These all involve the pilosebaceous unit — the hair follicle and its oil gland. They are frequently mistaken for one another, which matters, because a treatment that helps one can aggravate another. Topical steroids, for instance, will settle many rashes but reliably make perioral dermatitis worse.

Rashes and inflammatory skin disease

Inflammatory skin disease is diagnosed less by what a rash looks like than by where it sits, how sharply it is bordered, and how it has behaved over time. Eczema and psoriasis can look alike in a single photograph and are usually separated by distribution and history.

Eczema
Psoriasis
Contact dermatitis
Hives
Rashes
Itching
Dry skin
Keratosis pilaris

Pigment, texture, and aging

Pigment cells respond to inflammation, hormones, and ultraviolet light, which is why marks left by acne, melasma, and sun damage share so much of their treatment. Nearly all pigment work depends on daily photoprotection — without it, results plateau or rebound.

Melasma
Hyperpigmentation
Anti-aging
Scars & keloids

Hair, nails, and sweat

Hair loss is a category rather than a diagnosis, and the treatments diverge sharply depending on which type is present. The distinction that matters most is scarring versus non-scarring, because scarring types destroy follicles permanently and reward being caught early.

Hair loss
Nail conditions
Excessive sweating

Growths, spots, and infections

This group spans benign growths, viral and fungal infections, and lesions that warrant a closer look. The useful signal with any spot is change — something that is new, growing, changing color, or behaving differently from your other spots is worth raising.

Warts
Cold sores
Fungal infections
Skin tags
Moles & spot checks

How dermatologic diagnosis works

Most of dermatology is diagnosed by pattern. A dermatologist is reading four things at once, and the combination is usually more informative than any one of them alone.

MorphologyThe basic shape of the lesion — whether it is flat or raised, fluid-filled or solid, scaly or smooth. This narrows the field faster than anything else, which is why a description like "a rash" is much less useful than "raised, ring-shaped, and scaly at the edge."
DistributionWhere it appears, and where it conspicuously does not. Eczema favors the creases of the elbows and knees; psoriasis favors the surfaces over them. The same lesion in a different location can mean a different diagnosis.
Time courseHow long it has been present, whether it comes and goes, and what it looked like at the start. Hives that resolve within a day behave differently from ones that persist, and that difference changes the workup.
HistoryWhat you have already tried, what you are taking, what runs in your family, and what changed shortly before it started. A treatment that failed is diagnostic information, not a dead end.

Dermatology is also unusual among specialties in that the organ is fully visible. There is no imaging step between the physician and the finding — the evidence is right there on the surface, which is part of why so much of the field is built on trained visual pattern recognition.

Worth raising early

A mole or spot that is new, growing, changing color, bleeding, or simply behaving unlike your other spots deserves attention sooner rather than later. So does any hair loss that comes with scalp pain, burning, or scaling. Early is almost always easier to treat than late.

Not sure which one you have?

That is a normal place to start, and sorting it out is the job. Describe what you are seeing and Dr. Porto will take it from there.

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This page is general health information, not medical advice, and reading it does not create a physician–patient relationship. Treatment decisions depend on your individual history and examination. If you are experiencing a medical emergency, call 911 or go to the nearest emergency department.