Aug, 28 2025
Patchy, marbled, or blotchy skin can feel unnerving-especially when it shows up out of nowhere. The goal here is simple: name the most likely reasons your skin looks mottled, show you what each one usually looks like, and give you a plan you can actually follow. Expect straight answers, UK-friendly advice, and clear red flags so you know when it’s time to call your GP.
What you’re probably trying to do right now: 1) put a name to the pattern on your skin, 2) decide if it’s urgent, 3) pick the right at‑home fix or clinical treatment, 4) stop it coming back, and 5) know what tests or referrals to ask for if you need them.
- TL;DR: Most mottling is either blood‑flow related (cold, veins, autoimmune) or pigment related (sun, hormones, post‑inflammation); a good history + pattern usually points the way.
- Quick rule: If mottling comes with pain, fever, shortness of breath, sudden swelling, or looks bruise‑like and spreads-seek urgent care.
- Cold, net‑like purple patterns that fade when warm = livedo/cutis marmorata; warm up and monitor.
- Brown, patchy face/cheeks during pregnancy or with hormones = melasma; sun protection + azelaic acid; see GP if persistent.
- Itchy, scaly pale/brown patches on trunk in summer = tinea versicolor; antifungal shampoo/cream usually clears it.
What causes mottled skin discoloration? The top 10 (and how to recognise them)
Think of mottled skin discoloration as two broad buckets: 1) circulation/vascular patterns (often purple/blue, net‑like, change with temperature), and 2) pigment changes (brown, tan, or pale patches that don’t shift minute‑to‑minute).
-
Livedo reticularis / cutis marmorata (cold‑induced)
What it looks like: A lacey, net‑like purple pattern on thighs, arms, or trunk, worse in cold, fading with warmth. Common on chilly UK mornings.
Why it happens: Superficial blood vessels narrow in the cold. Often harmless, but can be secondary to autoimmune disease if persistent or one‑sided with pain.
What to do: Warm clothing, avoid cold exposure, see if it resolves when warm. Red flags: pain, ulcers, one‑sided persistent pattern, history of clots (consider GP review). NHS and BAD describe this pattern clearly (NHS 2024; BAD 2023).
-
Erythema ab igne (chronic heat exposure)
What it looks like: A net‑like brown/purple stain where a hot water bottle, space heater, or laptop rests (shins, thighs, abdomen).
Why it happens: Low‑grade heat damages skin over time.
What to do: Stop the heat source. Many cases fade over months; stubborn patches may need prescription retinoids or dermatology review. Documented by BAD and AAD guidance.
-
Post‑inflammatory hyperpigmentation (PIH)
What it looks like: Flat brown spots or patches after acne, eczema, bug bites, or friction. Darker skin tones often get more noticeable PIH.
Why it happens: Inflammation triggers extra melanin.
What to do: Daily SPF 30+ (better, SPF 50) broad‑spectrum; gentle skincare. Actives with best evidence: azelaic acid 15-20%, retinoids at night, vitamin C 10-20%, niacinamide 4-5%. AAD and Cochrane reviews support these options (AAD 2022; Cochrane 2021).
-
Sun damage (mottled pigmentation and sun spots)
What it looks like: Irregular brown macules and an uneven tone on face, hands, forearms; worse after years outdoors.
Why it happens: UV exposure increases melanin and breaks down collagen.
What to do: Broad‑spectrum SPF 30+ every morning, reapply outdoors. Consider retinoids, vitamin C, and in‑clinic options like chemical peels or intense pulsed light (IPL) after GP/dermatologist assessment. BAD and NICE emphasise sun protection as first‑line (NICE 2023; BAD 2023).
-
Melasma (hormonal pigment)
What it looks like: Symmetrical brown patches on cheeks, forehead, upper lip. Common in pregnancy or with hormonal contraception.
Why it happens: Hormones + sun. Heat can also trigger it.
What to do: Daily SPF 50, shade, hats; azelaic acid, cysteamine, kojic acid. Hydroquinone is prescription‑only in the UK; ask your GP/dermatologist. Many need long‑term maintenance. AAD and BAD outline these treatments (AAD 2022; BAD 2023).
-
Tinea versicolor (yeast overgrowth)
What it looks like: Patchy pale, pink, or brown flaky areas on chest, back, shoulders; colour looks more obvious after sun. Mild itch.
Why it happens: Malassezia yeast overgrows in warm, humid conditions.
What to do: Antifungal shampoo (ketoconazole, selenium sulfide) as a body wash for several days, or topical antifungal cream. Pigment can take weeks to normalise after the yeast is gone. BAD and NHS provide simple protocols (BAD 2023; NHS 2024).
-
Venous insufficiency / stasis changes
What it looks like: Brownish, mottled staining around the ankles/shins, swelling by evening, varicose veins, possible eczema‑like itch.
Why it happens: Weakened vein valves cause pooling and iron deposition in skin.
What to do: Leg elevation, regular walking/calves activation, weight management, and compression stockings (properly fitted). See a GP for Doppler ultrasound if ulcers, severe swelling, or sudden pain (rule out DVT). NICE has clear care pathways (NICE 2022).
-
Medication‑induced pigmentation
What it looks like: Slate‑grey or blue‑grey patches (minocycline), brownish facial pigment (amiodarone), diffuse darkening (antimalarials), or photosensitive darkening in sun‑exposed areas.
Why it happens: Drug deposition or melanin changes.
What to do: Never stop a prescription without advice. Book a GP medication review to consider alternatives and monitoring. AAD and MHRA safety communications list common culprits (AAD 2022; MHRA 2024).
-
Autoimmune or clotting disorders (lupus, vasculitis, antiphospholipid syndrome)
What it looks like: Persistent, sometimes painful livedo; ulcers; tender purplish spots; other systemic signs (joint pain, headaches, miscarriages).
Why it happens: Inflammation or microclots affect vessels.
What to do: See your GP for blood tests (FBC, ESR/CRP, ANA, antiphospholipid antibodies) and possible referral to dermatology/rheumatology. Urgent care if sudden pain, cold limb, or ulceration. NHS and NICE outline red flags (NICE 2023; NHS 2024).
-
Systemic illness and infection (including sepsis, shock)
What it looks like: Sudden mottling with cold, clammy skin, fast heart rate, confusion, fever, or feeling very unwell. This is an emergency pattern.
What to do: Seek urgent care. NHS 111/999 pathways in the UK triage these signs for sepsis/shock (NHS 2024). Do not self‑treat.
-
Vitiligo and other depigmentation disorders
What it looks like: Milky‑white patches with sharp edges, sometimes symmetric around body openings, hands, or over joints. Contrast with surrounding skin can look “mottled.”
Why it happens: Autoimmune loss of melanocytes.
What to do: Sun protection, camouflage if desired, and GP referral for topical steroids or calcineurin inhibitors; targeted light therapy is sometimes used. BAD patient leaflets explain options (BAD 2023).
How to fix mottled skin: a step‑by‑step plan you can follow
Use this simple flow to get from “what is this?” to “what do I do next?”
-
Match the pattern
- Lacey purple that changes with temperature: think livedo/circulation.
- Brown/tan patches that don’t change minute‑to‑minute: think pigment (sun, hormones, PIH).
- Pale or brown flaky patches on trunk: think tinea versicolor.
- Shin staining + swelling/varicose veins: think venous insufficiency.
- Sudden mottling + feeling unwell: treat as urgent.
-
Check for red flags
- Painful purplish lesions, ulcers, cold limb, severe headache, chest pain, breathlessness, fever, new confusion, or rapid spread.
- If any apply-seek urgent care. If not, move to step 3.
-
Start the right home fix
- Cold‑induced livedo: warm layers, keep core warm; monitor.
- PIH/sun damage: daily SPF 30-50; start azelaic acid in the morning and a retinoid at night 2-3 times a week; add vitamin C if tolerated.
- Melasma: SPF 50 + shade; azelaic acid; avoid heat exposure (saunas); speak to GP about prescription options if it lingers.
- Tinea versicolor: ketoconazole or selenium sulfide shampoo as a body wash (neck‑to‑waist) daily for 5-7 days; repeat monthly if it recurs.
- Venous insufficiency: 30-60 minutes daily walking, calf raises, leg elevation; consider compression stockings after GP fitting.
- Erythema ab igne: stop the heat source; consider a retinoid cream at night.
-
Decide on medical review
- Book a GP review now if: pigment after a new medication, persistent livedo without cold trigger, leg ulcers, or if under‑the‑skin bleeding spots (purpura) appear.
- Ask about: bloods (FBC, thyroid, B12, iron studies if diffuse darkening; ANA if autoimmune suspicion), Doppler ultrasound for venous disease, STI testing if warranted, fungal microscopy for tinea that recurs.
-
Stick with a timeline
- PIH and melasma: sunscreen results are immediate in preventing darkening; visible fading usually 6-12 weeks with actives.
- Tinea versicolor: scaling resolves in 1-2 weeks; colour normalises over 4-8 weeks.
- Erythema ab igne: can take months to fade once heat is stopped.
- Venous changes: swelling improves in weeks with compression and movement; staining may persist or lighten slowly.
Evidence notes for the above: sunscreen and topical retinoids/azelaic acid have solid support from AAD practice guidelines (2022) and a 2021 Cochrane review on hyperpigmentation; tinea versicolor protocols are standard in BAD/NHS patient guidance; venous care follows NICE recommendations; autoimmune red flags and testing pathways are consistent with NHS primary care guidance (2022-2024).
| Situation | Likely bucket | Self‑care | See GP | Urgent |
|---|---|---|---|---|
| Lacey purple that fades when warm | Livedo/cold | Warmth, monitor | If persistent, painful, or one‑sided | - |
| Brown flat spots after acne/eczema | PIH | SPF + azelaic/retinoid | If scarring or worsening | - |
| Symmetric facial brown patches | Melasma | SPF50 + azelaic | For prescription options | - |
| Itchy, flaky, pale/brown trunk patches | Tinea versicolor | Antifungal shampoo/cream | If recurrent or uncertain | - |
| Shin staining + swelling/varicose veins | Venous insufficiency | Walk/elevate/compression | Ultrasound, ulcer care | Sudden calf pain/swelling |
| New mottling + fever/unwell | Systemic/infection | - | - | Urgent care |
Quick tools: checklists, examples, and answers
Use these to tighten your routine and avoid common mistakes.
Daily and weekly checklist to fade pigment safely
- Morning: broad‑spectrum SPF 30-50 on face/neck/hands; reapply if outdoors.
- Morning or evening: azelaic acid 15-20% (pea‑sized amount) for PIH/melasma.
- Night: retinoid 2-3 nights/week to start (retinol 0.3-0.5% or GP‑prescribed tretinoin). Increase slowly.
- Optional morning: vitamin C 10-20% if you tolerate it (skip if stinging).
- Moisturiser with ceramides or glycerin to keep the barrier calm.
- Patch test new actives behind the ear for 48 hours before full use.
- Take photos every 2 weeks in the same light to track progress.
Fast fixes by cause
- Cold‑triggered livedo: thermal base layers, keep core warm, avoid smoking/nicotine (worsens vessel spasm).
- Erythema ab igne: remove heat source now; consider a night retinoid; if it thickens or stays dark, ask for a dermatology referral.
- Tinea versicolor: apply ketoconazole 2% shampoo from neck to waist, leave 5-10 minutes, rinse-daily for 5-7 days; repeat once weekly for a month if it recurs.
- Venous insufficiency: 10 sets of 20 calf raises spaced through the day, elevate legs above heart 15 minutes twice daily, ask GP about compression fitting.
- Medication pigment: photo‑document the colour change, list meds/supplements, book a GP medication review; protect from sun in the meantime.
Common pitfalls (skip these)
- Skipping sunscreen while using brightening actives-your gains will stall.
- Layering five new actives at once-if you irritate the skin, PIH can get darker.
- Using steroid creams long term on the face without medical advice-can thin skin and worsen pigment.
- Self‑stopping heart or autoimmune meds due to pigment changes-always consult your GP first.
Two quick examples
- Student, 22, Manchester: lacey purple thighs after cycling in winter, fades after a hot shower. No pain. Likely cold‑induced livedo. Fix: extra layers, warm‑up before rides. Review only if it becomes persistent or painful.
- Office worker, 48: mottled brown ankles, swelling by evening, itch around varicose veins. Likely venous insufficiency. Fix: daily walks, calf raises, GP for Doppler and proper compression; protect skin to prevent ulcers.
Mini‑FAQ
- How long until pigment fades? PIH/melasma: 6-12 weeks for first visible changes, longer for full fading. Tinea pigment can lag 4-8 weeks after the yeast is gone.
- Do I need a blood test? If mottling is persistent, painful, one‑sided, or you have other symptoms (ulcers, headaches, miscarriages, clot history), ask for bloods (FBC, ESR/CRP, ANA, antiphospholipid) and possible imaging.
- Is hydroquinone available in the UK? Yes, by prescription. OTC hydroquinone is not legal. Alternatives: azelaic acid, cysteamine, kojic acid, arbutin.
- Which SPF? Look for “broad‑spectrum” UVA/UVB, SPF 30-50. Apply two finger lengths for the face and neck. Tinted mineral formulas help block visible light, which matters in melasma.
- Can darker skin tones use retinoids? Yes-start low, go slow, moisturise, and patch test. Avoid irritation to reduce risk of rebound PIH.
- When is mottling dangerous? If paired with pain, cold limb, fever, chest pain, breathlessness, new confusion, or rapid spread-seek urgent care.
Next steps and troubleshooting
- If you’re pregnant or planning to be: focus on SPF, hats, shade, and azelaic acid; skip retinoids and hydroquinone unless your clinician advises.
- If you’re on meds linked to pigment (minocycline, amiodarone, antimalarials): do not stop them yourself. Book a GP review to weigh risks/benefits and discuss alternatives. Log any sun exposure.
- If your skin is sensitive: add one new active every 2-3 weeks. If stinging lasts more than 10 minutes or you peel, cut back frequency.
- If you have darker skin tones (Fitzpatrick IV-VI): prioritise barrier care, niacinamide, azelaic acid; add retinoids very gradually; consider a tinted SPF for visible‑light protection.
- If tinea versicolor keeps coming back: after clearing, use antifungal shampoo as a preventive wash once weekly for 1-2 months during warm seasons. Wash gym gear hot and change out of sweaty clothes quickly.
- If venous issues limit movement: try seated calf raises and ankle pumps; ask your GP about referral to a vascular clinic if ulcers or severe symptoms.
What to ask your GP (so the appointment is useful)
- “Could this be livedo from an autoimmune issue, and do I need bloods (ANA, antiphospholipid)?”
- “Do I need a Doppler ultrasound to check my leg veins?”
- “Is a prescription retinoid or hydroquinone suitable for my pigment?”
- “Could any of my medications be causing this, and what are safe alternatives?”
- “If this is tinea versicolor, should I use a preventive antifungal plan?”
Credible sources behind this guidance (no links included): NHS clinical guidance and patient info (2022-2024); British Association of Dermatologists patient leaflets (2023); American Academy of Dermatology guidelines on hyperpigmentation and sun protection (2022); NICE guidance on venous disease and dermatology referrals (2022-2024); MHRA medication safety updates (2024); Cochrane Review on topical treatments for hyperpigmentation (2021).