Pediculosis (ICD-11: 1G00): Complete Coding and Diagnostic Guide

1. Introduction

Pediculosis represents one of the most common parasitic infestations worldwide, affecting millions of people annually regardless of socioeconomic conditions. It is a condition caused by lice, small hematophagous insects that feed on human blood and can infest different areas of the body, including the scalp, body, and pubic region. Although not considered a serious disease, pediculosis causes significant discomfort, impacts patients' quality of life, and in some cases can lead to secondary complications such as bacterial infections resulting from scratching.

The clinical importance of pediculosis transcends individual discomfort. In collective settings such as schools, daycare centers, shelters, and long-term care institutions, transmission can occur rapidly through direct contact between people or sharing of personal items such as combs, brushes, hats, and bedding. This characteristic of easy dissemination makes pediculosis a relevant public health problem, requiring coordinated strategies for prevention, early diagnosis, and appropriate treatment.

Correct coding of pediculosis using the ICD-11 code 1G00 is fundamental for various aspects of medical practice and health management. It enables precise epidemiological monitoring of infestations, facilitates appropriate allocation of resources for control programs, ensures adequate reimbursement of diagnostic and therapeutic procedures, and contributes to the production of reliable statistical data on the prevalence and incidence of this condition. Healthcare professionals should understand not only the clinical aspects of pediculosis, but also the specific criteria for correct application of this code in the context of the International Classification of Diseases in its 11th revision.

2. Correct ICD-11 Code

The correct code for pediculosis in the International Classification of Diseases, 11th revision, is 1G00.

This code is inserted in the broad category of Infestations by ectoparasites, which encompasses various conditions caused by parasites that live on the external surface of the human body. Pediculosis represents one of the main ectoparasitic infestations found in daily clinical practice.

The official ICD-11 definition for code 1G00 establishes that pediculosis comprises infestations of the skin, hair, or genital region caused by lice that live directly on the human body or on hats and other clothing. Transmission generally occurs through direct contact with an infested person, although indirect contact with contaminated objects is also possible.

The classification recognizes three distinct types of pediculosis: head lice (caused by Pediculus humanus capitis), body lice (caused by Pediculus humanus corporis), and pubic lice (caused by Pthirus pubis). The most characteristic and common symptom of infestation is intense pruritus in the affected area, which typically intensifies progressively between three to four weeks after initial infestation, a period necessary for the immune system to develop sensitization to louse saliva.

This code has two specific subcategories that allow greater precision in coding when necessary, reflecting the need for differentiation between types of pediculosis for epidemiological and therapeutic purposes.

3. When to Use This Code

The code 1G00 should be used in specific clinical situations where there is confirmation or strong diagnostic suspicion of louse infestation. Below, we present detailed practical scenarios:

Scenario 1: Child with intense itching of the scalp A school-age child is brought to the health service with a complaint of intense itching of the scalp for two weeks. On physical examination, the healthcare professional identifies the presence of nits (louse eggs) firmly adhered to hair strands, especially in the nape region and behind the ears. Excoriations on the scalp resulting from scratching are also observed. In this case, code 1G00 is fully indicated, as there is direct evidence of infestation through visualization of nits, and the clinical presentation is compatible with head pediculosis.

Scenario 2: Adult with itching in the pubic region An adult patient seeks medical care reporting intense itching in the pubic and genital region for approximately three weeks. During careful physical examination, the healthcare professional identifies small brownish insects adhered to pubic hair, in addition to nits. The patient reports having had recent sexual contact with a new partner. Code 1G00 is appropriate for documenting this infestation by pubic lice, commonly known as "crabs."

Scenario 3: Person in situation of social vulnerability An individual living in precarious hygiene conditions presents with complaints of generalized itching on the body, especially on the trunk and limbs. On examination, multiple scratch lesions are observed, some with signs of secondary infection. Careful inspection of the seams of the patient's clothing reveals the presence of body lice and nits. Code 1G00 should be used to record this infestation by body lice.

Scenario 4: Outbreak in collective institution During investigation of an outbreak in a long-term care facility, several residents present simultaneous complaints of itching of the scalp. Systematic evaluation of all residents identifies multiple cases of head louse infestation, with the presence of live parasites and nits. Code 1G00 should be applied for each diagnosed individual, allowing proper documentation of the outbreak and implementation of control measures.

Scenario 5: Patient with mixed infestation A patient presents simultaneously with infestation by head lice and pubic lice, a situation that can occur in contexts of personal neglect or multiple exposures. Code 1G00 is used to document the presence of pediculosis, and can be specified through subcategories when the registration system allows for greater detail.

Scenario 6: Diagnosis during routine examination During a routine or pre-admission physical examination, the healthcare professional incidentally identifies the presence of nits in the patient's hair, even in the absence of active complaints of itching. This situation, although the patient may be asymptomatic, still constitutes pediculosis and should be coded as 1G00, as the presence of parasites or their viable eggs confirms the infestation.

In all these scenarios, the fundamental criterion for using code 1G00 is confirmation of the presence of lice (adults or nymphs) or their viable nits through direct visual examination, preferably with the aid of a magnifying glass or fine-tooth comb.

4. When NOT to Use This Code

It is essential to recognize situations where code 1G00 should not be applied, avoiding coding errors that may compromise medical records and epidemiological data.

Scalp pruritus without evidence of infestation Many dermatological conditions cause itching of the scalp, including seborrheic dermatitis, psoriasis, atopic dermatitis, allergic reactions, and fungal infections. If careful examination does not reveal the presence of lice or viable nits, code 1G00 should not be used. In these cases, the appropriate code should reflect the correct dermatological diagnosis.

Empty nits after treatment After successful treatment of pediculosis, shells of empty nits may remain adhered to hair strands for weeks or months. The presence of empty nits alone, without live parasites or viable nits (which appear closer to the scalp and have a shinier appearance), does not constitute active infestation and should not be coded as 1G00. This situation represents a residual finding of previously treated infestation.

Other ectoparasite infestations Infestations by scabies mites (scabies), fleas, ticks, or other ectoparasites should not be coded as 1G00. Each of these conditions has specific codes in ICD-11. Differentiation is made through identification of the specific parasite during clinical or laboratory examination.

Myiasis Myiasis, infestation by fly larvae, has its own code (1G01) and should not be confused with pediculosis. While pediculosis involves adult lice that remain on the skin surface, myiasis is characterized by penetration of larvae into subcutaneous tissue, causing distinct nodular or ulcerative lesions.

Isolated insect bites Reactions to isolated bites from mosquitoes, bedbugs, or other insects do not constitute pediculosis and require different coding. Pediculosis implies established infestation with parasites living continuously on the host, not isolated bite events.

Delusional parasitosis Some patients present with unshakeable conviction of being infested by parasites, despite repeated examinations revealing no objective evidence of infestation. This psychiatric condition, known as delusional parasitosis or Ekbom syndrome, requires appropriate psychiatric coding, not code 1G00.

Clear distinction between true pediculosis and these other conditions is essential for accurate coding and appropriate clinical management.

5. Step-by-Step Coding Process

Step 1: Assess diagnostic criteria

The diagnosis of pediculosis is fundamentally based on direct physical examination and visual identification of parasites or their eggs. The healthcare professional should perform a thorough inspection of the affected area under good lighting, preferably using a magnifying glass or magnifier.

For head pediculosis, carefully examine the scalp, especially the nape region, behind the ears, and the crown, where lice preferentially locate due to ideal temperature. Use a fine-toothed metal comb to comb hair strands over white paper, facilitating visualization of parasites that may fall.

Viable nits appear as ovoid structures, white-grayish in color, firmly adhered to the hair shaft less than 6-7 millimeters from the scalp. Nits located more than 1 centimeter from the root are usually empty or nonviable. Adult lice measure approximately 2-3 millimeters, have brownish coloration, and move rapidly when exposed.

For pubic pediculosis, inspect pubic hair, perianal region, axillary hair, and in extensive cases, eyelashes and eyebrows. Pubic lice are smaller and wider than head lice, with a "crab-like" appearance.

For body pediculosis, parasites are rarely found on the body itself, but rather in the seams and folds of the patient's clothing, especially undergarments and bedding. Inspect these areas carefully.

Confirmation can be made by placing the suspected parasite on a glass slide under a microscope for definitive identification, although this is rarely necessary in clinical practice.

Step 2: Verify specifiers

After confirming the presence of pediculosis, determine the specific type of infestation, as this influences treatment and may be relevant for more detailed coding when the system allows subcategories.

Identify whether it is head pediculosis (Pediculus humanus capitis), body pediculosis (Pediculus humanus corporis), or pubic pediculosis (Pthirus pubis). This differentiation is based on the location of the infestation and the morphological characteristics of the parasites.

Assess the intensity of infestation: mild (few parasites and nits), moderate, or severe (massive infestation with multiple parasites). This assessment, although subjective, may be relevant for therapeutic decisions.

Document the duration of symptoms when possible, as itching typically begins or intensifies 3-4 weeks after initial infestation in previously unexposed individuals, but may occur earlier in reinfestation.

Identify secondary complications such as excoriations, secondary bacterial infection (impetigo, folliculitis), regional lymphadenopathy, or in rare cases of chronic body pediculosis, cutaneous changes such as hyperpigmentation.

Step 3: Differentiate from other codes

1G01 - Myiasis: This condition involves infestation by fly larvae, not lice. In myiasis, nodular or ulcerative skin lesions are observed with the presence of larvae that penetrate subcutaneous tissue. The patient frequently reports a sensation of movement under the skin. The fundamental difference is the etiological agent (dipteran larvae versus lice) and clinical presentation (deep lesions versus superficial infestation).

1G02 - External hirudiniasis: Refers to the attachment of leeches (hirudineans) to the skin or mucous membranes. Unlike lice, leeches are larger annelids, visible to the naked eye, that attach temporarily for feeding and then detach. The clinical presentation is completely distinct, with bleeding lesions at the attachment site.

1G03 - Phthiriasis: This specific code refers exclusively to infestation by Pthirus pubis (pubic louse). The differentiation from the general code 1G00 depends on the coding system used in the institution. In some contexts, 1G00 is used as a comprehensive code for all pediculoses, while in others, more specific codes such as 1G03 are preferred when detailed coding is available.

Correct differentiation requires careful examination and precise identification of the etiological agent present.

Step 4: Necessary documentation

For adequate coding and complete medical record, document the following elements:

Mandatory documentation checklist:

Specific location of infestation (scalp, body, pubic region)
Confirmation of the presence of live lice and/or viable nits
Description of physical examination findings
Duration of symptoms when known
Intensity of itching and its temporal evolution
Presence of excoriations or other secondary lesions
Signs of secondary infection if present
History of known or probable exposure
Affected household or institutional contacts
Previous treatments performed and their results
Hygiene conditions and identified risk factors

Additional recommended elements:

Clinical photographs when appropriate and with consent
Record of guidance provided to the patient
Prescribed therapeutic plan
Guidance on treatment of contacts
Environmental control measures recommended
Scheduling of follow-up evaluation to confirm eradication

This complete documentation not only justifies the 1G00 coding, but also provides the basis for continuity of care and appropriate epidemiological monitoring.

6. Complete Practical Example

Clinical Case:

Maria, 8 years old, is brought by her mother to the health unit with the chief complaint of "intense itching on the head" for approximately three weeks. The mother reports that the itching started mildly but progressively intensified, and is currently so intense that it is disrupting the child's sleep. Maria attends regular school and the mother mentions that other children in her class have also presented similar symptoms recently.

During the history of present illness, the mother denies that Maria has a history of cutaneous allergies, dermatitis, or other previous dermatological conditions. The child has no fever, general malaise, or other systemic symptoms. The mother reports that she tried washing her daughter's hair with increased frequency, but the symptoms persisted.

On physical examination, Maria appears in good general condition, active and cooperative. Examination of the scalp reveals multiple linear excoriations in the occipital and bilateral retroauricular regions, resulting from scratching. There are no evident signs of secondary infection, such as pustulation or honey-crusted lesions. The posterior cervical lymph nodes are slightly enlarged and mobile, consistent with lymph node reaction to local irritation.

Using a fine-toothed metal comb, the healthcare professional carefully combs Maria's hair over white paper. During this procedure, two live adult lice are identified and captured, measuring approximately 2-3 millimeters, with brownish coloration and active movement. Careful inspection of the scalp, especially near the nape and behind the ears, reveals numerous viable nits firmly adhered to hair shafts approximately 3-5 millimeters from the root. These nits present white-grayish coloration and shiny appearance, differentiating from empty nits that would be located further from the scalp.

The remainder of the physical examination reveals no other significant findings. There are no signs of infestation in other body areas, pubic region, or body hair.

Step-by-Step Coding:

Analysis of diagnostic criteria: The case presents all criteria necessary for diagnosis of head pediculosis. There is objective confirmation through direct visualization of live adult lice and viable nits on the scalp. The clinical presentation is typical, with progressive pruritus beginning three weeks ago (consistent with the 3-4 week sensitization period), secondary excoriations from scratching, and epidemiological history suggestive of transmission in a school environment.

Differentiation from other diagnoses: The differential diagnosis was appropriately excluded. This is not seborrheic dermatitis (absence of characteristic oily scaling), psoriasis (absence of erythematous scaly plaques), atopic dermatitis (absence of atopic history and eczematous lesions), nor fungal infection (absence of alopecia or scaling typical of scalp tinea). The presence of live parasites confirms active infestation, differentiating from residual finding of empty nits post-treatment.

Code chosen: 1G00 - Pediculosis

Complete justification: Code 1G00 is fully appropriate for this case based on the following grounds:

Parasitological confirmation: Direct identification of live adult lice (Pediculus humanus capitis) and viable nits, constituting objective proof of active infestation.
Characteristic clinical presentation: Intense pruritus with typical temporal evolution (3 weeks), preferential location (occipital and retroauricular region), and compatible secondary lesions (excoriations).
Epidemiological context: History of exposure in a collective environment (school) with other known cases, consistent with the transmission pattern of pediculosis.
Exclusion of alternative diagnoses: Absence of characteristics suggesting other dermatological conditions or infestations by different ectoparasites.

Complementary codes: In this specific case, there is no need for additional codes, as no complications requiring separate coding were identified. If documented secondary bacterial infection (impetigo, for example) had been present, an additional code for cutaneous infection would be appropriate. If cervical lymphadenopathy were more pronounced or clinically significant, complementary coding could be considered, although it is generally considered part of the presentation of pediculosis.

Documentation in medical record: "8-year-old patient with complaint of intense itching on the scalp for 3 weeks, progressive. On examination: multiple excoriations in occipital and retroauricular region. Live adult lice and numerous viable nits adhered to hair shafts identified near the scalp. Posterior cervical lymph nodes slightly enlarged. Diagnosis: Head pediculosis (ICD-11: 1G00). Prescribed appropriate topical treatment, guidance on treatment of household contacts and environmental control measures. Follow-up in 7-10 days for reassessment."

7. Related Codes and Differentiation

Within the Same Category:

1G01: Myiasis Myiasis represents infestation by fly larvae (Diptera) that penetrate and develop in human tissues. The fundamental differentiation from code 1G00 is based on the etiological agent and clinical presentation. While pediculosis involves lice that remain on the skin surface feeding on blood, myiasis is characterized by larvae that invade subcutaneous tissues, creating nodular or ulcerative lesions with a central opening. Patients with myiasis frequently report sensation of movement under the skin and may visualize larvae emerging from the lesion. Code 1G01 should be used when there is confirmation of dipteran larvae, not lice.

1G02: External hirudiniasis This code refers to the attachment of leeches (hirudineans) to the skin or mucous membranes. Unlike lice, which are small insects that establish continuous infestation, leeches are significantly larger annelids (can reach several centimeters), visible to the naked eye, that attach temporarily for blood feeding and then detach spontaneously. External hirudiniasis typically occurs after exposure to fresh water or humid environments where leeches inhabit. Clinical presentation includes visualization of the attached leech and persistent bleeding at the site after its detachment due to anticoagulants present in its saliva. Use 1G02 when the agent is a leech, not lice.

1G03: Phthiriasis Phthiriasis specifically designates infestation by Pthirus pubis, the pubic louse or "crab louse." This code represents a specification within the spectrum of pediculosis. The relationship between 1G00 and 1G03 may vary according to institutional coding system: some use 1G00 as a comprehensive code for all forms of pediculosis, while others prefer to specify using 1G03 when the infestation is confirmed to be by pubic louse. Differentiation is based on morphological identification of the parasite (Pthirus pubis has a wider and shorter body, resembling a crab) and preferential location (pubic hair, perianal, axillary, rarely eyelashes and eyebrows). When available and appropriate, use 1G03 for greater specificity in cases of pubic pediculosis.

Important Differential Diagnoses:

Scabies: Caused by the mite Sarcoptes scabiei, presents with intense pruritus with characteristic nocturnal worsening, papular and vesicular lesions in typical locations (interdigital spaces, wrists, axillae, periumbilical region, genitalia), and presence of subcutaneous burrows. Microscopic identification of the mite, eggs, or feces in skin scraping confirms the diagnosis. Code distinct from 1G00.

Seborrheic dermatitis: Causes yellowish oily scaling of the scalp, unlike the firmly adherent nits of pediculosis. Absence of parasites on examination. Requires appropriate dermatological code.

Scalp ringworm: Fungal infection that causes areas of alopecia with scaling and hair breakage. Diagnosis confirmed by mycological examination. Code different from 1G00.

Contact dermatitis: May cause scalp pruritus after use of hair products, but presents with diffuse erythema and absence of parasites. History of exposure to a new product is suggestive.

Precise differentiation requires careful clinical examination and, when necessary, complementary tests for definitive identification of the etiological agent.

8. Differences with ICD-10

In the International Classification of Diseases in its 10th revision (ICD-10), pediculosis was coded in category B85, with specific subdivisions:

B85.0: Pediculosis due to Pediculus humanus capitis (head louse)
B85.1: Pediculosis due to Pediculus humanus corporis (body louse)
B85.2: Pediculosis, unspecified
B85.3: Phthiriasis (infestation by Pthirus pubis)
B85.4: Mixed infestation by lice

The transition to ICD-11 brought significant structural changes in the organization and coding of pediculosis. The code 1G00 in ICD-11 represents a more simplified and unified approach, although it maintains the possibility of specification through subcategories when necessary.

Main structural changes:

ICD-11 adopts a different alphanumeric structure, with codes starting with numbers followed by letters, contrasting with ICD-10 structure which used a letter followed by numbers. This change reflects the complete reorganization of the classification to allow greater flexibility and future expandability.

The parent category in ICD-11 is "Infestations by ectoparasites," providing logical grouping of related conditions. In ICD-10, pediculosis was included in the chapter on "Infectious and parasitic diseases," but the hierarchical organization was less intuitive.

Practical impact:

For healthcare professionals, the main practical change involves familiarization with the new code 1G00 replacing the previous B85.x codes. Health information systems and electronic health records must be updated to incorporate the ICD-11 structure.

Coding in ICD-11 maintains the ability to specify when clinically relevant through subcategories, preserving the diagnostic granularity necessary for epidemiological and research purposes, while offering a unified main code (1G00) for general use.

For purposes of historical data comparison and longitudinal epidemiological studies, it is important to maintain correspondence tables between ICD-10 codes (B85.x) and ICD-11 (1G00), allowing time series analysis that spans the transition between classifications.

Clinical documentation should specify the type of pediculosis (head, body, or pubic) regardless of the code used, as this information remains clinically and epidemiologically relevant even with coding unification.

9. Frequently Asked Questions

1. How is a definitive diagnosis of pediculosis made?

The diagnosis of pediculosis is essentially clinical, based on direct visual identification of live lice or viable nits. The most effective method involves thorough examination of the affected area under good lighting, preferably with a magnifying glass. For head pediculosis, the use of a fine-toothed metal comb over white paper facilitates the capture and visualization of parasites. Viable nits are located close to the scalp (less than 6-7 mm from the root), have a bright white-grayish coloration, and are firmly adhered to the hair shaft. Adult lice measure 2-3 mm, have a brownish coloration, and move actively when exposed. Laboratory tests are generally not necessary, as visual identification is sufficient. In doubtful cases, the parasite can be placed under a microscope for definitive morphological confirmation.

2. Is treatment available in public health systems?

Yes, treatments for pediculosis are widely available in public health systems in many countries. Therapeutic options include topical pediculicidal treatments (such as permethrin, malathion, or topical ivermectin) and, in specific cases, oral treatment with ivermectin. Public health systems generally provide these medications free of charge or at reduced cost. In addition to medication, health professionals provide essential guidance on mechanical removal of nits with a fine comb, treatment of contacts, washing of clothes, and environmental control measures. School health programs frequently include educational and pediculosis control actions. Specific availability may vary depending on the region and structure of the local health system, but pediculosis is recognized as a public health problem that requires universal access to treatment.

3. How long does treatment last?

The duration of complete pediculosis treatment generally extends for 2-3 weeks. The initial application of topical pediculicide eliminates most adult lice and nymphs, but may not destroy all eggs (nits). Since nits hatch in approximately 7-10 days, a second application of treatment is recommended 7-10 days after the first to eliminate newly hatched lice before they reach reproductive maturity. Daily mechanical removal of nits with a fine comb throughout the treatment period significantly increases the success rate. After the two pediculicide applications, a follow-up examination is recommended 2-3 weeks later to confirm complete eradication. Treatment of household contacts should be simultaneous to prevent reinfestation. Environmental control measures (washing clothes, cleaning combs and brushes) should be maintained throughout the treatment period.

4. Can this code be used in medical certificates?

Yes, code 1G00 can and should be used in medical certificates when appropriate. Pediculosis, especially in school-age children, frequently requires temporary exclusion from collective activities until effective treatment begins, justifying the issuance of a medical certificate. Proper documentation with ICD-11 code 1G00 provides formal justification for exclusion, being accepted by educational institutions and employers. Many schools and daycare centers have specific policies requiring children with pediculosis to remain home until after the first application of pediculicidal treatment, a measure aimed at reducing transmission in collective settings. The medical certificate documents the diagnosis, justifies temporary exclusion, and, when appropriate, authorizes return to activities after treatment begins. Correct coding is also important for epidemiological recording and outbreak monitoring in institutions.

5. Can pediculosis cause serious complications?

Although pediculosis itself is not considered a serious disease, it can lead to secondary complications that require medical attention. The most common complication is secondary bacterial infection resulting from excoriations caused by intense scratching. Bacteria such as Staphylococcus aureus and Streptococcus pyogenes can infect scratch lesions, causing impetigo, folliculitis, or cellulitis. In rare cases, more serious infections such as abscesses or suppurative lymphadenitis may occur. Chronic and neglected body pediculosis can cause persistent skin changes, including hyperpigmentation, skin thickening, and lichenification. Historically, body lice have importance as vectors of serious diseases such as epidemic typhus, relapsing fever, and trench fever, although these conditions are rare currently. Psychosocial impacts, including social stigma, embarrassment, anxiety, and sleep disturbance due to pruritus, also represent significant consequences that affect quality of life.

6. How to prevent reinfestation after treatment?

Prevention of reinfestation requires a multifaceted approach. First, all household contacts should be examined and, if infested, treated simultaneously. Bedding, towels, and clothing worn in the last 2-3 days should be washed in hot water (above 60°C) and dried in a hot dryer, or isolated in a sealed plastic bag for 2 weeks (a period longer than the louse life cycle). Combs, brushes, and hair accessories should be washed in hot soapy water or immersed in diluted pediculicide. Vacuuming of upholstered furniture, carpets, and vehicle seats removes fallen parasites. Objects that cannot be washed can be isolated in sealed plastic bags for 2 weeks. Education about avoiding sharing personal items (combs, brushes, hats, scarves, pillows) is fundamental. In collective settings, institutional measures include periodic surveillance examinations, notification of cases to those responsible, and clear policies on management of infestations. It is important to emphasize that pediculosis is not related to lack of personal hygiene, reducing stigma that may hinder notification and control.

7. Is there resistance to available treatments?

Yes, louse resistance to pediculicides is a growing concern documented in various regions. Resistance to permethrin and other pyrethroids has been increasingly reported, resulting in therapeutic failures. Resistance mechanisms include mutations in genes encoding sodium channels in the louse nervous system (mutations known as "kdr"). Resistance to malathion and other organophosphates has also been documented, although less frequently. This reality makes it essential that health professionals stay updated on treatment efficacy in their region. When there is therapeutic failure after adequate treatment, consider the possibility of resistance and opt for a pediculicide of a different chemical class. Ivermectin (topical or oral) represents an important alternative in cases of resistance. Mechanical removal with a fine comb is not subject to resistance and should always be a component of treatment. Rational use of pediculicides, avoiding unnecessary or prophylactic applications, helps delay the development of resistance.

8. What is the difference between viable nits and empty nits?

Differentiating viable nits from empty ones is crucial to determine whether there is active infestation or only residue from previous treated infestation. Viable nits are located close to the scalp (typically less than 6-7 mm from the root), as they are newly deposited on hair close to the skin where the temperature is ideal for embryonic development. They have a white-grayish coloration with a bright or pearly appearance, regular ovoid shape, and are firmly adhered to the hair shaft. When observed against light, they may appear full. Empty nits, on the other hand, are located farther from the scalp (usually more than 1 cm from the root), as they were deposited weeks before and the hair has grown. They have a more whitish or opaque yellowish coloration, may appear flattened or irregular, and when observed carefully, the operculum (lid through which the nymph emerges) may be open. Empty nits represent residual shells after hatching or death of the embryo, not constituting active infestation. The presence of only empty nits does not justify pediculicidal treatment, although their mechanical removal is recommended for aesthetic reasons and to avoid diagnostic confusion.

Conclusion

Proper coding of pediculosis using ICD-11 code 1G00 requires comprehensive understanding of the clinical, diagnostic, and epidemiological aspects of this common condition. Health professionals must master the diagnostic criteria, recognize situations where the code is appropriate, differentiate it from other similar conditions, and properly document all relevant clinical findings. The transition from ICD-10 to ICD-11 brought structural changes that, while requiring initial adaptation, provide a more logical and expandable coding system. Effective management of pediculosis transcends individual treatment, requiring a public health approach that includes treatment of contacts, environmental control measures, and community education to prevent transmission and reinfestation.

External References

This article was prepared based on reliable scientific sources:

References verified on 2026-02-03

Pediculosis

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