Description: Discover signs of unhealthy skin that need attention—from persistent acne to unusual moles. Learn when skin issues signal serious problems and when to see a dermatologist.
Let me tell you about the weird patch on my arm I ignored for six months.
It was just a small, slightly raised, discolored spot. Not painful. Not spreading rapidly. Just... there. I told myself it was probably nothing. Dry skin, maybe. Or a weird freckle. I'd Google it eventually. Definitely didn't need a doctor for something so minor.
Fast forward six months: turns out it was basal cell carcinoma. Skin cancer. Completely treatable when caught early (which mine was, thankfully), but the dermatologist's exact words were "why did you wait so long to come in?"
Because I ignored my skin's warning signs. Because I convinced myself minor changes weren't worth medical attention. Because "it's probably fine" is humanity's default response to concerning symptoms.
Here's what nobody tells you about signs of unhealthy skin: your skin is your body's largest organ, and when something's wrong, it often shows up there first. Ignoring obvious signals because they're not immediately painful or life-threatening is how minor issues become major problems.
Skin health warning signs range from "get this checked today" to "probably fine but worth monitoring." The challenge is knowing which is which when you're Googling symptoms at 2 AM and convincing yourself you definitely have a rare tropical disease based on a single pimple.
When to see a dermatologist should be obvious but isn't, because we're all collectively terrible at taking skin changes seriously until they're impossible to ignore.
So let me give you the unhealthy skin symptoms you absolutely shouldn't dismiss, the ones that might be concerning, and the ones that are probably fine but worth understanding.
Because your skin is trying to tell you things.
You should probably listen.
The Absolute "See a Doctor NOW" Signs
Emergency skin symptoms that need immediate attention:
1. Moles That Change (The ABCDE Rule)
What to watch for:
A - Asymmetry: One half doesn't match the other half. Normal moles are symmetrical.
B - Border: Irregular, ragged, notched, or blurred edges. Normal moles have smooth borders.
C - Color: Multiple colors (brown, black, tan, red, white, blue) in one mole. Normal moles are one color.
D - Diameter: Larger than a pencil eraser (6mm), though melanomas can be smaller.
E - Evolving: Any change in size, shape, color, elevation, or new symptom (bleeding, itching, crusting).
Why it matters: Melanoma (deadly skin cancer) often appears as changing moles.
Action: See dermatologist immediately if any ABCDE criteria apply.
Don't wait: "I'll watch it for a few months" could be the difference between early-stage (95% survival) and late-stage (much worse prognosis).
2. Non-Healing Sores
What it looks like: Cut, wound, or sore that doesn't heal within 2-3 weeks.
Keeps returning: Heals and comes back in same spot repeatedly.
Might be: Basal cell carcinoma, squamous cell carcinoma, or infection.
Warning signs:
- Bleeds easily
- Crusts over but doesn't heal
- Develops raised edge
- Changes in appearance
Action: Dermatologist visit if anything hasn't healed in 3 weeks.
3. Sudden, Severe Rash with Fever
What it means: Possible allergic reaction, infection, or systemic illness.
Especially concerning if:
- Accompanied by fever, difficulty breathing, or swelling
- Spreads rapidly
- Involves mucous membranes (mouth, eyes, genitals)
- Follows new medication
Possible causes: Stevens-Johnson syndrome (medical emergency), severe allergic reaction, meningitis (if also have headache, stiff neck).
Action: Emergency room, not dermatologist appointment.
4. Dark Streaks Under Nails
What it looks like: Brown or black vertical line under nail.
Why it's concerning: Could be subungual melanoma (melanoma under nail).
Especially if: Streak widens, nail bed darkens, extends to surrounding skin, or you can't remember injuring that nail.
Exception: More common and often benign in people with darker skin tones (melanonychia striata).
Action: Dermatologist evaluation to rule out melanoma.
5. Yellowing Skin (Jaundice)
What it looks like: Skin and whites of eyes turn yellow.
What it means: Liver problem, gallbladder issue, or blood disorder.
Not a skin issue: It's a symptom of internal disease showing up on skin.
Action: Doctor immediately (not dermatologist—primary care or ER).
6. Butterfly Rash Across Nose and Cheeks
What it looks like: Red, raised rash across cheeks and nose bridge (shaped like butterfly).
Possible cause: Lupus (autoimmune disease).
Especially with: Joint pain, fatigue, fever.
Action: Doctor for autoimmune screening.
The "Don't Panic But Get It Checked" Signs
Concerning but not emergency skin symptoms:
7. Persistent Acne That Doesn't Respond to Treatment
When it's concerning:
- Tried OTC treatments for 12 weeks with zero improvement
- Deep, painful cystic acne
- Acne suddenly appearing in adulthood
- Scarring developing
Might indicate: Hormonal imbalance (PCOS in women), stress, diet issues, or need for prescription treatment.
Why it matters: Persistent inflammatory acne can cause permanent scarring.
Action: Dermatologist for prescription options (retinoids, antibiotics, hormonal treatments, isotretinoin for severe cases).
8. Patches of Extremely Dry, Scaly Skin That Won't Heal
What it looks like: Thick, rough, scaly patches that don't improve with moisturizer.
Possible causes:
- Psoriasis (autoimmune)
- Eczema (chronic inflammation)
- Contact dermatitis (allergic reaction)
- Pre-cancerous actinic keratosis (rough patches from sun damage)
Red flags: Bleeding, cracking, spreading, or appearing on unusual areas.
Action: Dermatologist to diagnose and prescribe appropriate treatment.
9. Dark Patches (Hyperpigmentation) That Appear Suddenly
What it looks like: Dark spots or patches appearing where none existed.
Possible causes:
- Melasma (hormonal, often pregnancy or birth control)
- Post-inflammatory hyperpigmentation (after acne or injury)
- Sun damage
- Medication side effect
- Rarely: underlying disease (Addison's disease)
When concerning: Sudden appearance without clear cause, rapid spread, or accompanied by other symptoms.
Action: Dermatologist to determine cause and treatment options.