Dermatologists who treat skin blemishes, melasma, and pigmentation disorders

A clear guide to understanding why skin changes color, what causes are common, and what signs warrant medical evaluation.

Before reading: En skinpaths We distinguish between opinion and evidence. To write this content, we prioritized indexed medical sources and recommendations from scientific societies. At the end, you will find the complete bibliography for your reference.
Important: This article is for informational purposes only and does not replace medical advice. If you have any questions, persistent symptoms, or your condition worsens, consult a healthcare professional.

Summary in 60 seconds

• “Spot” is a descriptive term: it refers to a change in the color or appearance of the skin, not a diagnosis in itself.
• The spots can be dark, light or even white; sometimes they are completely flat and other times they are accompanied by raised areas, scaling or thickening.
• Common causes include post-inflammatory hyperpigmentation, solar lentigines, melasma, pityriasis alba, pityriasis versicolor, and vitiligo.
• The sun has a significant influence on various types of spots, but it doesn't explain them all: other causes include previous inflammation, hormones, tumors, some infections, and certain autoimmune disorders.
• Fine scaling suggests inflammatory or fungal processes; a velvety appearance in folds or a lesion "stuck" to the skin suggests other causes.
• Many spots are benign, but a new lesion that changes, bleeds, or combines several colors should be checked to rule out the possibility that it is a tumor.
• The dermatologist can guide the diagnosis with clinical examination, dermatoscopy, Wood's lamp, scraping or biopsy, depending on the case.
• It is not advisable to start using depigmenting creams, acids or peels without first knowing what type of lesion it is.

What is a biosimilar

In dermatology, “skin spots” is a colloquial way of describing areas that change color compared to the surrounding skin. These may correspond to hyperpigmentation, hypopigmentation, depigmentation, or lesions that also change texture. From any perspective, it is important to understand that a “spot” is a sign, not a diagnosis. (Plensdorf 2017 , Nicolaidou 2014 )

Most of the time, context is more helpful than color alone: ​​it matters if the lesion itches, scales, is raised, appeared after acne or eczema, is located on the face or in skin folds, or is changing over time. When a spot is new and evolving, evaluation by a specialist is mandatory. Plensdorf 2017 Tran 2008 NICE 2015.

Why do they appear?

Spots (of non-neoplastic origin) appear, simply put, through four main mechanisms. The first is an increase in melanin, as occurs in post-inflammatory hyperpigmentation, melasma, or many "sun spots." The second is a decrease or loss of pigment, as in vitiligo, pityriasis alba, or some post-inflammatory hypopigments. The third is an alteration of the skin surface, as occurs in seborrheic keratoses or acanthosis nigricans. The fourth includes superficial infectious or inflammatory processes, for example, pityriasis versicolor. Davis 2010, Leung 2022, Wollina 2018, Popa 2019.

In practice, sun exposure, pre-existing inflammation, and hormonal changes are very common triggers. Melasma, for example, usually appears in sun-exposed areas and can be related to pregnancy, contraceptives, or other hormonal factors. Post-inflammatory hyperpigmentation often follows acne, dermatitis, friction, or procedures. AAD 2022b AAD 2022a

In dermatology, a spot is a clinical sign; it is almost never a diagnosis on its own.

What do they look like?

Dark spots typically appear as brown, grayish, or blackish areas. If they are symmetrical on the face and have irregular but relatively diffuse borders, melasma may be suspected; if they appear after acne, eczema, or insect bites, post-inflammatory hyperpigmentation is a common cause; if they predominate in sun-exposed areas over the years, solar lentigines should be considered in the differential diagnosis. AAD 2022a Davis 2010 Plensdorf 2017

Light or white spots have a variety of causes. Vitiligo usually produces more defined depigmented (rather white) areas; pityriasis alba usually causes less well-defined pale patches, especially on the faces of children and adolescents; pityriasis versicolor can cause lighter or darker spots with fine scaling, particularly on the trunk and shoulders; and idiopathic guttate hypomelanosis produces small white spots in areas with accumulated sun damage. Eleftheriadou 2022 PCDS 2022 DermNet 2021.

Texture also provides clues. If the area is dry or has fine scales, inflammatory or fungal causes should be considered. If the skin is dark, thickened, and has a velvety feel on the neck, armpits, or groin, acanthosis nigricans is a possibility. If it appears as a brown, "adherent" or waxy lesion, it could be seborrheic keratosis. If a patch combines several colors, has irregular borders, or is changing, it's no longer advisable to rely solely on its appearance and should be discussed with a specialist as soon as possible (because the possibility of it being a tumor is clear). Leung 2022 Popa 2019 Wollina 2018 Tran 2008

In what diseases or conditions do they usually occur?

The following classification is for guidance only. It combines clinical frequency and common causes in the general population; it is not intended to replace individual diagnosis nor to express an exact epidemiological hierarchy for all age groups and phototypes. Plensdorf 2017 Leung 2022.

1) Very frequent

1. Post-inflammatory hyperpigmentation. It usually appears after acne, eczema, bites, friction or irritation, and may persist longer in more pigmented skin. Davis 2010.
2. Solar lentigines (“sun spots” or “age spots”). These are usually benign pigmented lesions related to cumulative sun exposure. Plensdorf 2017 DermNet.
3. Melasma. It produces dark patches, especially on the face, with solar radiation and hormonal factors playing an important role. AAD 2022a AAD 2022b.
4. Pityriasis alba. More typical in childhood and adolescence, with pale and discreetly scaly patches, often linked to dry skin or mild eczema. PCDS 2022 BAD.

2) Frequent

1. Pityriasis versicolor. Superficial yeast infection of the skin; may cause light, dark, or pink spots and is usually more visible in warm, humid weather. Leung 2022 AAD.
2. vitiligo. It produces depigmented areas; its impact can be more emotional than physical, and it is important to differentiate it from other causes of light spots. Eleftheriadou 2022 AAD.
3. Seborrheic keratosis. These are very common benign lesions from middle age onwards, and are sometimes described as "spots" although they actually have a raised surface. Wollina 2018 AAD.
4. Acanthosis nigricans. It causes dark, velvety plaques in skin folds; it is often benign, but it can be associated with underlying problems and warrants review. Popa 2019 NHS.

3) Infrequent or less frequent, but very relevant

1. Idiopathic guttate hypomelanosis. Small white spots on sun-exposed limbs, especially with age; it is benign. DermNet 2021.
2. Pigmented lesions suspected of being melanoma or other skin tumors. They are less frequent than benign causes, but they are the ones that should not be overlooked. Tran 2008 NICE 2015.
3. Café-au-lait spots or other persistent pigmented lesions. Some are isolated and benign findings; others, depending on number and context, require clinical correlation. Plensdorf 2017.

When to consult?

Consult without delay if any of these situations arise:

• A stain nueva that grows or changes shape, color, or size. Tran 2008
• An injury with asymmetry, irregular edges, or multiple colors. Tran 2008 NICE 2015
• A stain that bleeds, scabs over, hurts, ulcerates, or does not heal. NICE 2015
• An injury that seemed "of old age" but is different from the rest or is changing. AAD 2021
• White spots that spread rapidly, affecting the face, hands, mucous membranes, or causing diagnostic uncertainty. Eleftheriadou 2022
• Dark, velvety patches of recent appearance on the neck, armpits or groin. NHS
• Sudden appearance of many new lesions or several spots that do not fit a clear pattern. AAD

What NOT to do?

A common mistake is treating all spots as if they were the same. They are not. Scraping, vigorously exfoliating, or “bleaching” the area without a diagnosis can further irritate the skin, worsen pigmentation, or delay the detection of a significant or potentially malignant lesion. AAD 2021 Popa 2019.

• Do not rub a dark stain on your neck or armpit thinking it is "dirt".". NHS AAD.
• Do not start using depigmenting creams, peels, or acids without knowing what the lesion is.. AAD 2021
• Do not assume that every white spot is vitiligo or that every scaly spot is "just dryness". AAD Leung 2022 PCDS 2022.
• Do not treat a supposed "age stain" before someone confirms that it really is one. AAD 2021

What does a dermatologist usually do?

The first step is usually a thorough medical history: when the spot appeared, whether it has changed, whether it itches or flakes, whether there has been acne, eczema, or a previous injury, whether there has been significant sun exposure, pregnancy, use of contraceptives, family history, or autoimmune diseases. Then, the entire skin is examined, not just the lesion of concern. (Plensdorf 2017 ; Eleftheriadou 2022 )

If the lesion is pigmented or suspicious, dermatoscopy provides additional information without invasive procedures. In cases of selective light or dark pigmentation, a Wood's lamp can help to better define certain alterations; if there is scaling and a fungal infection is suspected, a scraping can be taken for microscopy. NICE 2016 Dyer 2022 AAD.

When diagnostic uncertainty persists or melanoma or another relevant lesion is suspected, a biopsy may be necessary. It is not a routine step for all lesions, but it is very important when the clinical appearance does not allow for certainty. Tran 2008 AAD.

In some contexts, additional tests are also requested. For example, in vitiligo, studies related to autoimmunity or thyroid function may be considered, and in acanthosis nigricans, it may be reasonable to investigate underlying causes based on the medical history. Eleftheriadou 2022 AAD NHS.

Many spots are benign; however, a new spot that changes deserves evaluation by a specialist.

FAQ

Are all dark spots caused by the sun?

• No. The sun explains some of the lentigines and can worsen melasma, but there are also dark spots due to previous inflammation, acne, eczema, friction, or metabolic causes. AAD 2022b Popa 2019.

Are white patches always vitiligo?

• No. They can also be pityriasis alba, pityriasis versicolor, post-inflammatory hypopigmentation, or other conditions. The clinical pattern and, sometimes, Wood's lamp examination help to differentiate them. PCDS 2022 Leung 2022 Dyer 2022.

Can a cream simply remove them?

• It depends entirely on the cause. Some improve with sun protection, others require antifungal medication, others anti-inflammatory treatment, and some should not be treated before a diagnosis is confirmed. Evaluation by a specialist is very important before starting any treatment. Plensdorf 2017 AAD 2021

When should I really worry?

• When a lesion is new and changing, when it bleeds, scabs over, hurts, doesn't heal, or when a "spot" is clearly different from the others, it's wise to consult a dermatologist. Tran 2008 NICE 2015.

Can flaking patches be a fungal infection?

• Yes, sometimes. Pityriasis versicolor is a common cause of light or dark patches with fine scales, especially on the trunk and in warm or humid climates. Leung 2022 AAD.

Does a dermatologist always need a biopsy?

• No. Many lesions are diagnosed clinically. Biopsy is reserved for diagnostic doubts or suspicious lesions, especially if the goal is to rule out melanoma or other neoplasms. Plensdorf 2017 Tran 2008 AAD.

Bibliography and sources

• Plensdorf S, Liveratos M, Dada N. Pigmentation disorders: diagnosis and management. Am Fam Physician. 2017;96(12):797-804. Available in: PubMed.
• Davis EC, Callender VD. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. J Clin Aesthet Dermatol. 2010;3(7):20-31. Available in: PMC.
• Eleftheriadou V, Atkar R, Batchelor J, et al. British Association of Dermatologists guidelines for the management of people with vitiligo 2021. Br J Dermatol. 2022;186(1):18-29. Available in: PubMed.
• Leung AKC, Barankin B, Lam JM, Leong KF, Hon KL. Tinea versicolor: an updated review. Drugs Context. 2022;11:2022-9-2. Available in: PMC.
• Popa ML, Popa AC, Tanase C, Gheorghisan-Galateanu AA. Acanthosis nigricans: To be or not to be afraid. Oncol Lett. 2019;17(5):4133-4138. Available in: PubMed.
• Wollina U. Seborrheic keratoses – The most common benign skin tumor of humans. Clinical presentation and an update on pathogenesis and treatment options. Open Access Maced J Med Sci. 2018;6(11):2270-2275. Available in: PMC.
• Dyer JM, Foy VM. Revealing the unseen: a review of Wood's lamp in dermatology. J Clin Aesthet Dermatol. 2022;15(6):25-30. Available in: PMC.
• Tran KT, Wright NA, Cockerell CJ. Biopsy of the pigmented lesion—when and how. J Am Acad Dermatol. 2008. Available in: PubMed.
• American Academy of Dermatology Association. Melasma: overview [Internet]. 2022 Feb 15. Available in: AAD.
• American Academy of Dermatology Association. Melasma: causes [Internet]. 2022 Feb 15. Available in: AAD.
• American Academy of Dermatology Association. Vitiligo: diagnosis and treatment [Internet]. Available in: AAD.
• American Academy of Dermatology Association. Tinea versicolor: diagnosis and treatment [Internet]. Available in: AAD.
• American Academy of Dermatology Association. What can get rid of age spots? [Internet]. 2021 Sep 28. Available in: AAD.
• Primary Care Dermatology Society. Pityriasis alba [Internet]. 2022 May 28. Available in: PCDS.
• British Association of Dermatologists. Pityriasis alba [Internet]. Available in: BAD.
• DermNet NZ. Idiopathic guttate hypomelanosis [Internet]. Updated 2021 Jun. Available in: DermNet.
• DermNet NZ. Solar lentigo [Internet]. Available from: DermNet.
• National Institute for Health and Care Excellence. Melanoma: assessment and management. NICE guideline NG14 [Internet]. 2015 Jul 29; updated 2022 Jul. Available in: NICE.
• National Institute for Health and Care Excellence. Skin cancer quality standard: dermoscopy in specialist assessment of pigmented lesions [Internet]. 2016. Available in: NICE.
• NHS. Acanthosis nigricans [Internet]. Available in: NHS