Flat warts: on the face, hands and body, how to treat

Flat warts are small, slightly raised or subflat papules caused by infection with the human papillomavirus. They are most often multiple, grouped, and located on the face, back of the hands, forearms, and shins; in adults, they often occur in shaving areas due to the Koebner phenomenon (self-inoculation from microtrauma). They are smooth, matte, flesh-colored or yellowish-brown in appearance, approximately 1-5 mm in diameter, sometimes with tens or hundreds of elements in a single cluster. Although benign, their cosmetic significance and the risk of self-inoculation make them a common reason for consultation. [1]

Dermoscopy is the key to recognition: flat warts typically have uniform light-brown or yellowish areas with regularly distributed red dots (capillaries), without the pigment network characteristic of melanocytic lesions. Under a dermatoscope or with a light superficial cut, "blackheads" are usually absent: unlike common (vulgar) and plantar warts, the vascular component is less pronounced. This helps distinguish flat warts from acne, lentigo, seborrheic keratosis, and lichen planus. [2]

Virologically, flat warts are most often associated with human papillomavirus types 3 and 10, less commonly 28 and 49; typing is not routinely required because treatment decisions are based on clinical presentation and location rather than genotype. Pathogenesis involves infection of basal keratinocytes, localized hyperplasia, and the formation of thin, flat papules. Spontaneous regression is possible, especially in children and adolescents, but can take months or years, so many patients choose treatment for cosmetic reasons. [3]

It's important to remember that "flat warts" are not a single disease, but a clinical phenotype of human papillomavirus infection. The course varies from person to person: in some, warts quickly regress, while in others, they expand due to self-transfer, especially with shaving or scratching. Hence, the emphasis on gentle techniques, disciplined care, and patient education. [4]

Code according to ICD-10 and ICD-11

In the International Classification of Diseases, Tenth Revision, flat warts are coded in block B07 "Viral warts": most often B07.8 "Other viral warts" or B07.9 "Viral wart, unspecified"; if necessary, the location is indicated. This is convenient for accounting and insurance reporting, although clinical management is always based on the phenotype and site. [5]

The International Classification of Diseases, Eleventh Revision, includes block 1E80, "Skin Warts," with the following breakdown: 1E80 (general categories), 1E80.0, "Digital and periungual warts," 1E80.1, "Plantar warts," etc. For flat warts, family code 1E80 is used, specifying the location (face, hands, extremities). This breakdown reflects the clinical presentation and facilitates the comparability of studies and tactics. [6]

Table 1. Examples of coding of flat warts

Clinical situation	ICD-10	ICD-11
Flat warts on the face	B07.8 / B07.9	1E80 (indicating "facial skin")
Flat warts on the back of the hands	B07.8	1E80 (brush localization)
Multiple flat warts on the extremities	B07.8	1E80 (localization "upper/lower limb")

Epidemiology

Flat warts are part of the general "family" of cutaneous warts, with a prevalence of 3-10% in adults and 15-44% in children and adolescents, depending on cohort and age. They are particularly common on the face and hands, reflecting the role of close contact and microtrauma. These figures explain the significant burden on pediatric and dermatology services. [7]

Flat warts often appear in "waves": clusters of 20-100 warts have been described in schoolchildren and young adults, and in adults, in shaved areas (cheeks, shins). In close-knit settings (families, clubs, sports), familial and group cases are observed. Such clusters require not only treatment for the individual but also hygiene measures in the surrounding community. [8]

Spontaneous regression within 12–24 months is common but unpredictable; in adults, the time to regression is longer, and relapses are more frequent. This is an important consideration when choosing between watchful waiting and active therapy. The choice depends on the location, social discomfort, and the risk of self-inoculation. [9]

After the pandemic, the frequency of visits for warts in adults remains high, due to the "cosmetic sensitivity" of the facial area and the widespread availability of removal procedures. However, the evidence base reminds us that there are no "miracle cures," and the effectiveness of these methods is moderate, with keratolytics and some destructive methods being superior. [10]

Reasons

The etiologic agent is human papillomavirus (HPV), which has a tropism for the skin; types 3 and 10 are most commonly identified for flat warts, while types 28 and 49 are less common. The virus penetrates through microlesions, infecting basal keratinocytes, and as they differentiate, clinical papules form. Typing usually does not change tactics and remains a research tool. [11]

Sharing towels, razors, cosmetic applicators, and the habit of touching the face facilitates the spread; in adolescents, it's shaving; in children, it's close play. It's important to explain the mechanisms of self-transference to patients to reduce the number of new elements. This is part of therapy, not "take-home advice." [12]

Flat warts have a different appearance than "common" and plantar warts: they are thin, matte, and lack coarse hyperkeratosis, so they have different dermatoscopic features and respond differently to treatment methods. For example, aggressive cryotherapy on the face more often results in discoloration than in permanent clearance. [13]

Individual immune reactivity explains the differences in the course of the disease: in some patients, the elements disappear without intervention, while in others they persist for years. This justifies interest in immunotherapy, which "prompts" the immune system to recognize virus-infected cells. [14]

Risk factors

Triggering factors include microtrauma to the skin, shaving, epilation, scratching, and maceration. This is why lesions most often appear on the cheeks, shins, backs of the hands, and forearms. Those who work with their hands are also exposed to microcuts and friction. Correcting these habits reduces autoinoculation and accelerates remission. [15]

The increased risk among schoolchildren and students is associated with close contact, shared personal care items, and sports. Family clusters are common: sharing towels and razors significantly increases the spread of the disease within the home. Simple household measures effectively reduce the incidence of the disease. [16]

Dry skin and a compromised barrier also increase susceptibility—cracks and peeling become gateways for the virus to enter. Regular emollients and gentle hygiene aren't just cosmetics, but prevention of new lesions in those predisposed. [17]

Finally, immune status influences the duration of the disease and relapses. Immunodeficiency conditions, stress, and sleep deprivation are associated with more persistent clusters in some patients, which is taken into account when choosing a strategy: immunotherapy and step-by-step procedures are more often used. [18]

Pathogenesis

After the virus penetrates the basal layer of the epidermis, keratinocyte proliferation is triggered, but without pronounced hyperkeratosis—hence the "flat" appearance of the papules. Histologically, verruca plana is characterized by orthokeratosis, acanthosis, and large keratinocytes with koilocytosis. These changes correlate with dermatoscopic "light brown areas" and punctate vessels. [19]

The Koebner phenomenon explains the linear "tracks" of papules along shaving or scratching lines. Any repeated microtrauma increases the local viral load and the number of elements. Therefore, advice on replacing blades, shaving gel, and technique is part of medical prevention, not just a household recommendation. [20]

The immune system often causes spontaneous regression, justifying a wait-and-see approach for a small number of lesions and low cosmetic risk. However, for multiple clusters, it makes sense to combine topical treatments with procedures to speed up clearance. [21]

A separate nuance is the weak vascular component of flat warts: it explains why “blood dew drops” and blackheads are less typical, and why classic “aggressive” cryotherapy protocols do not always provide high results, but increase the risk of dyschromia on the face. [22]

Symptoms

Typically, these are multiple, smooth, slightly raised papules 1-5 mm in size, ranging in color from flesh-colored to yellowish-brown, with a matte surface. They are most often located symmetrically on the face (cheeks, forehead), the back of the hands and forearms, and the shins, especially in shaved areas. Itching and pain are usually minimal. [23]

Under a dermatoscope, uniform light-brown/yellowish areas, regularly distributed red dots/punctate vessels, and an absence of a melanocytic network are visible. This increases the accuracy of clinical diagnosis and reduces the need for biopsy. [24]

A common complaint is the appearance of new lesions next to existing ones, especially after shaving or vigorous washing with hard brushes. This is typical autoinoculation, requiring adjustments to care and technique. With proper patient education, the rate of appearance of new papules is significantly reduced. [25]

Emotional and cosmetic discomfort are important factors, especially in adolescents and adults with facial localization. Discussing realistic timeframes and expected results (usually weeks and months, not "days") increases compliance and reduces the risk of traumatic self-treatment. [26]

Classification, forms and stages

Based on phenotype, flat warts are classified as single or multiple (clusters); the latter are more common and often form linear scars along microtrauma lines. By location, they are classified as facial, manual (hands/forearms), and shins/thighs; treatment approaches differ due to the varying risk of dyschromia and scarring. By duration, they are classified as fresh, subacute, and chronic. [27]

Dermoscopy reveals uniform fields of pinpoint vessels in verruca plana; the absence of "blackheads" distinguishes it from common/plantar warts. This is taken into account when choosing a technique: overly aggressive destruction of the face is undesirable; a gradual, gentle approach is preferable. [28]

Severity can be assessed by: area (number of lesions), activity of self-transfer, facial involvement, and response to previous therapy. This stratification helps decide whether to limit treatment to topical retinoids/5-fluorouracil or move on to cryotherapy, laser, or immunotherapy. [29]

Clinical "look-alikes" for differentiation include comedonal acne, lichen planus (flat, violaceous papules), seborrheic keratosis, lentigo, and molluscum contagiosum. Errors are especially common on the face, so dermatoscopy is the first-line standard. [30]

Complications and consequences

The main problem is cosmetic defects and self-inoculation with expansion of the affected area. Post-inflammatory hyper- or hypopigmentation is possible with trauma, especially in patients with a high phototype. Therefore, overly aggressive techniques on the face should be avoided. [31]

Destructive procedures (cryotherapy, curettage, laser) on the face carry the risk of discoloration and fine scarring, which should be discussed in advance. Proper sun protection after procedures reduces the likelihood of noticeable scars. The choice of protocol is always individual. [32]

A secondary bacterial infection rarely develops due to scratching or inadequate home "self-treatment." In such cases, the first priority is care, antiseptics as indicated, and delaying destruction until the inflammation subsides. Then, return to step-by-step therapy. [33]

Psychological stress in adolescents and young adults is a compelling argument for active yet gentle treatment. A plan that combines care, topical preparations, and gentle procedures is usually better tolerated and produces predictable cosmetic results. [34]

When to see a doctor

An in-person consultation is necessary for multiple clusters on the face, rapid growth of lesions, ineffectiveness of over-the-counter treatments within 8-12 weeks, or severe cosmetic discomfort. This will allow us to confirm the diagnosis and select a gentler treatment plan. [35]

Seek immediate medical attention if signs of a secondary infection appear: increasing pain, purulent crusts, increasing redness, and fever. In such situations, destruction is postponed, and sanitation and care take precedence. [36]

If the lesions appear atypical (asymmetry, multicolor, ulceration, rapid changes), dermatoscopy is necessary and, if in doubt, a biopsy to exclude other diagnoses. Diagnostic caution is especially important on the face. [37]

Finally, in cases of immunodeficiency, pregnancy, a pronounced tendency to scarring or a dark phototype, the treatment plan is selected individually with an emphasis on minimizing the risk of dyschromia and scarring. [38]

Diagnostics

The first step is a clinical examination and dermatoscopy. Flat warts are characterized by uniform light-brown or yellowish areas with pinpoint vessels, no pigment network, and no "black thrombosed dots." This increases accuracy without invasive procedures. [39]

The second step is an assessment of the Koebner phenomenon: elements along the lines of shaving, scratching, or friction, as well as a search for new lesions in areas of frequent contact. This examination helps adjust care and prevent self-transfer. [40]

Laboratory testing and human papillomavirus typing are not routinely necessary. Biopsy is indicated only in cases of atypical findings, diagnostic doubts, or to rule out other dermatoses and tumors. In cosmetically significant areas, dermatoscopic observation and gentler methods are preferred. [41]

Assessing the “weight of the problem” (number of elements, location, timing, previous treatment and tolerability) helps to formulate a step-by-step plan: from topical retinoids/5-fluorouracil to cryotherapy and, if refractory, to immunotherapy or laser. [42]

Table 2. Minimal diagnostic algorithm for suspected flat warts

Step	What are we doing?	What are we looking at?
1. Examination + dermatoscopy	Confirm the phenotype	Light brown/yellow areas, punctate vessels, no pigment network
2. Identify self-transference	Localization along injury lines	Shaving, scratching, friction
3. Eliminate "doubles"	Differential diagnosis	Acne, lichen planus, molluscum, keratosis, lentigo
4. Decide on a biopsy	Only when in doubt	Atypia, rapid changes, ulcer

Differential diagnosis

Flat warts are often confused with comedonal acne due to their similar size and the "scattered" appearance on the face. However, comedonal acne typically features comedonal "blackheads" and inflammatory papules/pustules, while dermatoscopy does not reveal the typical uniform areas with pinpoint vessels. Treatment is fundamentally different. [43]

Lichen planus produces flat, purple papules, often with a sheen and Wickham's reticulum; it is often itchy and leaves pigmentation. Dermoscopy and clinical examination allow for rapid diagnosis. Incorrect wart-like destruction in this case can worsen scarring. [44]

Seborrheic keratoses and lentigines are more common in adults and the elderly: they have different dermatoscopic patterns (pseudocysts of the corneal plug, mosaic, pigmented network), whereas flat warts have a vascular rather than pigmented pattern. When in doubt, dermatoscopy is preferable to immediate destruction. [45]

Molluscum contagiosum is a smooth, dome-shaped papule with an umbilicated depression; dermatoscopically, it has a central "crater-like" area. Misdiagnosis is rare upon careful examination, but in children, the diagnoses are sometimes confused. [46]

Table 3. "Flat warts" versus clinical doubles

Sign	Flat warts	Acne	Lichen planus	Seborrheic keratosis/lentigo
Color/surface	Nude-yellowish, matte	Comedones, inflammation	Purple, shiny	Pigment patterns
Dermatoscopy	Uniform fields + point vessels	There is no typical pattern	Bela/Wickham mesh	Pseudocysts/network
Pain/itching	Minimum	Often painful/itchy	Often itching	No
Tactics	Soft Topics/Step-by-Step Procedures	Acne therapy	Anti-inflammatory	Observation/removal

Treatment

The first layer of therapy is a topical keratomodulatory approach. For the face and hands, most patients start with retinoids (tretinoin cream/gel 0.025-0.05% or adapalene 0.1%): these normalize keratinization, reduce the number of warts, and are gentle. An "every other day" regimen with subsequent daily titration is often used; photoprotection and irritation control are important. The effectiveness of tretinoin for flat warts has been confirmed by pilot and comparative studies. [47]

The second line of topical treatment is 5-fluorouracil (usually a 5% cream), often combined with low-concentration salicylic acid to enhance penetration. On the face, it is used topically and in short courses under the supervision of a physician to reduce the risk of irritation and dyschromia; on the back of the hands and extremities, a more active regimen may be necessary. The combination of 5-fluorouracil with a keratolytic has historically demonstrated a better response than monotherapy. [48]

Imiquimod's use as an immunomodulator is limited due to its irritant potential, particularly on the face. It is appropriate to consider it when retinoids and 5-fluorouracil are insufficiently effective or contraindicated. The decision is individualized, based on an assessment of the patient's skin type and tolerance for local reactions. [49]

Liquid nitrogen cryotherapy remains a common procedure, but aggressive protocols are not ideal for flat warts on the face due to the risk of pain, blistering, discoloration, and scarring. The evidence is generally moderate: meta-analyses and reviews show that cryotherapy is not always significantly superior to salicylic acid, and that the results are better for the hands than for the feet. On the face, it is wiser to use short, gentle cycles or prioritize topical treatments. [50]

Combinations of "pre-softening + brief cryotherapy" are helpful for denser lesions, especially on the outside of the face. Reducing the stratum corneum improves heat exchange and access to the affected cells, increasing effectiveness with fewer cycles. In any scenario, the patient is informed of the risks and healing timeframes. [51]

Immunotherapy with intralesional antigens (e.g., standardized Candida antigen) is an option for multiple and refractory cases, particularly in areas outside the facial area or when the patient is ready for injections. Recent reviews and meta-analyses from 2024 to 2025 have shown comparable or better complete and "distant" (effect on distant lesions) responses compared to alternatives, with generally mild side effects. The regimen and dosage should be selected according to current protocols. [52]

Hardware-based methods (laser, photodestruction) are used when conservative approaches fail or when there is a clear cosmetic need in selected patients. They provide a quick visual effect but require experience to minimize the risk of scarring and dischromia, especially on the face. Careful aftercare and sun protection are essential after the procedure. [53]

Systemic and topical retinoids "off-label" continue to be studied: randomized trials comparing oral isotretinoin and topical tretinoin for multiple flat warts are underway. For now, such approaches are only appropriate in the hands of specialists and for those refractory to standard treatments. [54]

A maintenance care program is key to reducing recurrences: gentle cleansing without harsh brushes, disposable blades/electric razors with gentle technique, separate towels, no scraping, and regular sun protection of the face. These steps reduce autoinoculation and pigmentation. When combined with topical therapy, they increase the chance of sustained remission. [55]

It's important to discuss expectations upfront: most treatments require weeks or months, not a "one-visit" approach. On the face, it's best to take a step-by-step approach: first, a retinoid ± 5-fluorouracil spot treatment, then gentle treatments for residual lesions, and only if refractoriness persists should we move on to injectable immunotherapy or laser. This approach minimizes scarring while maintaining a reasonable rate of clearing. [56]

Table 4. Main treatment options for flat warts: what to choose and when

Method	Where appropriate	Strengths	Limitations/Risks
Topical retinoids (tretinoin/adapalene)	Face, hands	Gentle, accessible, good for clusters	Irritation, sun protection required
5-fluorouracil (often with low salicylic acid)	Face (points), limbs	More effective than monotherapy	Irritation/dyschromia due to errors
Cryotherapy (delicate cycles)	Off-face; on-face - selectively	Quick effect	Pain, blisters, dyschromia/scarring
Immunotherapy (Candida antigen, etc.)	Multiple/refractory	Effect on distant foci	Injections, local pain
Laser/devices	Selected cases	One-step visual result	Price, risk of traces

Prevention

Avoid sharing towels, razors, and cosmetic applicators; wash your hands after contact with the elements. In families and groups, these simple measures reduce household transmission and the number of new outbreaks. Regularly replace blades and avoid shaving dry. [57]

Reduce microtrauma: gentle cleansing, avoiding harsh brushes and scrubs on the face, using gentle shaving techniques, and gentle hair removal. Use sun protection during topical treatment to reduce the risk of post-inflammatory dyschromia. This is especially important for patients with a darker skin tone. [58]

Maintain the skin barrier: regularly apply emollients to your hands and areas prone to dryness to reduce the entry point for the virus through microcracks. Patient education is essential: do not pick, cut, or rub until the skin squeaks. [59]

Follow-up visits allow for adjustments to the treatment plan, promptly removing residual elements, and preventing relapses. Often, 1-2 visits are sufficient to adjust home therapy and strategies. [60]

Table 5. Self-transfer prevention guide

Situation	What to do	For what
Shaving/Epilation	Gentle technique, disposable blades	Less of the Koebner phenomenon
Hygiene	Separate towels/brushes/applicators	Less household transmission
Care	Gentle cleansing, emollients, SPF	Lower risk of dyschromia and cracks
Behavior	Do not cut, do not rub	Fewer new outbreaks

Forecast

In children and adolescents, spontaneous regression is highly likely within 12-24 months; in adults, the course is often protracted and recurrent. Properly selected topicals and gentle procedures reduce the time to visible clearance, but require patience. Cosmetic outcomes are better with a step-by-step approach. [61]

Relapses are associated with autoinoculation and incomplete eradication of affected cells. The most sustainable results are achieved by programs that combine care, topical therapy, and, if necessary, procedures. In refractory cases, immunotherapy increases the chances of clearing distant lesions. [62]

Overall, the prognosis is favorable: flat warts are benign, do not "malignant," and are usually manageable. The main challenge is finding a balance between effectiveness and cosmetic safety, especially on the face. This is achieved through an individualized plan and patient education. [63]

Table 6. What influences the prognosis

Factor	Influence
Age (children/teenagers)	Faster spontaneous regression
Localization (face)	Selection of gentle techniques, risk of dyschromia
Self-inoculation	Increases the area and duration of treatment
Commitment to care	Reduces relapses

FAQ

Should flat warts be treated if they don't bother you?
Not always. In some patients, they regress within 12-24 months. However, if they are located on the face, quickly "spread," or cause cosmetic discomfort, treatment is appropriate. The decision should be made in consultation with a doctor. [64]

What's better for the face: creams or cryotherapy?
For the face, treatments often start with topical retinoids and/or 5-fluorouracil spot treatments: these are gentle and effective for many. Cryotherapy is used sparingly or postponed, given the risk of dyschromia. [65]

Why do new lesions appear after shaving?
It's the Koebner phenomenon: the virus enters micro-damages. Gentle technique, fresh blades, gel/foam, avoiding dry shaving, and using separate razors can help. [66]

Does immunotherapy with injections work?
Yes, intralesional antigens have demonstrated good complete and "distant" responses in refractory warts in new reviews. This method is used as indicated and not necessarily on the face. [67]

Is there a one-time "magic" procedure?
No. Most methods are moderately effective and require a series of steps. Combinations, proper care, and sun protection can reduce scars and improve results. [68]

Table 7. Quick answers for the patient

Question	Short answer
Are flat warts dangerous?	Benign, but contagious by contact
How long does it take to treat?	Often weeks or months, not “days”
What comes first?	Retinoid ± 5-fluorouracil spot treatment
When are the injections?	For multiple/refractory lesions
How to avoid traces?	Gentle techniques + SPF