Current understanding of frictional dermatoses: A review

Introduction

Human skin is continually exposed to internal and external dynamic as well as static forces. The skin is normally flexible and can resist mechanical trauma to a considerable degree. However, an excess of these forces can abnormally affect the structure and function of the skin, setting the stage for the development of a skin disorder.

The term ‘frictional dermatoses’ encompasses a variety of entities such as frictional dermatitis, frictional melanosis, frictional pigmentary dermatoses and certain other named conditions, many of which are confusing. Friction is defined as the resistance experienced by a body when it comes in contact with another. Any imbalance in the frictional forces may lead to acute or chronic injury. Friction can also involve the mucosae^1-4 hair^5-8 and nails.^9,10

Frictional dermatoses is an under-recognised entity with no clear-cut definition. The authors propose to define frictional dermatoses as ‘a group of disorders caused by repetitive trauma to the skin as a result of friction of varying aetiology which can have a wide range of cutaneous manifestations depending on the type of insult.’

The exact prevalence of frictional dermatoses as a separate entity is unknown. However, various studies have reported the prevalence of individual conditions. A study from Germany reported that 21.6% (89/412) musicians had musical instrument related frictional skin disorders.^11,12 Friction accounted for 11.3% of occupational dermatoses due to non-glove personal protective equipment amongst healthcare workers in UK.^1,11

Materials and Methods

Authors who conducted the review include a group of dermatologists and postgraduate students from various institutions. They are members of the Resident Connect Committee of the Indian Association of Dermatologists Venereologists and Leprologists of the Delhi State Branch. It was a voluntary exercise proposed by the Chairperson of the Resident Connect Committee, Delhi State Branch. After a framework was decided on by participation of all authors on a virtual platform, different sections of the ‘review of literature’ were assigned to each. Literature was reviewed through PubMed, Medscape, Medline, ResearchGate and Google Scholar using the terms ‘frictional dermatitis,’ ‘friction and skin,’ ‘dermatoses and culture,’ ‘clothing dermatitis,’ ‘friction melanosis,’ ‘PPE induced dermatoses in COVID-19 era,’ etc. A total of 122 articles were reviewed and 100 articles were shortlisted for inclusion in the study, after removing duplications. The selected articles included brief communications, letters to editor, case reports, case series, observational studies, review articles and randomised controlled trials. The review was followed up with further deliberation and a new definition and classification for frictional dermatoses was formulated. The rising incidence of mechanical dermatoses in the COVID-19 era was also emphasised upon.

Predisposing Factors

Friction not only causes new dermatoses in individuals but can also exacerbate existing ones.¹⁰ The susceptibility of an individual’s skin to friction differs and is influenced by factors both extraneous and inherent, such as the presence of pre-existing diseases and genetic or racial differences, respectively [Table 1].

It is important to identify the predisposing factors that may be largely apparent or sometimes inconspicuous, but which are critical in the management of frictional dermatoses.

Pathogenesis

In simple terms, friction is the rubbing of one surface over the other or the force that resists movement between two bodies [Figure 1].¹⁹ The manifestation of friction related skin injury depends on the following factors:

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Figure 1:

Pathogenesis of frictional dermatoses. Friction is the rubbing of one surface over the other or the force that resists movement between two bodies. The manifestation of friction related skin injury depends on: type of friction which can be static or dynamic; intensity of the force (low or high); and, nature of the surface which includes body site, moisture content and the coefficient of friction

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Classification

As previously outlined, no single definition exists for frictional dermatoses and therefore currently there is no accepted classification encompassing the wide range of conditions that can be categorised under this entity. We propose a classification that takes into consideration the morphology, histopathological characteristics, anatomical region affected and the major predisposing factors such as the occupation of the individuals most commonly affected. This allows for a quick clinical diagnosis and treatment planning. However, it must be noted that the entities may not be specific to the occupation they are grouped under and may be found in patients with other occupations too.

Primary frictional dermatoses

Primary frictional dermatoses include entities where repeated friction is the major etiological factor responsible for development of the lesion. These conditions may be further classified based on the major predisposing factor such as the occupation, cultural or religious practices and the anatomical region affected [Figure 2], as outlined in Table 2.

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Figure 2:

Important frictional dermatoses based on the location. Frictional dermatoses may be classified based on the major predisposing factor such as the occupation, cultural or religious practices and the anatomical region affected

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Table 2: Classification of primary frictional dermatoses

Entity	Primary Frictional Dermatoses
	Anatomical Region
	Generalised	Head and Neck	Trunk	Limbs	Hair	Mucosa	Nails
1. Occupational
A. Sports Related	-	-	Joggers nipples17	Pool palms21 Rower’s hands20 Athlete’s nodules17 Talon noir22 Skater’s toe/toenail23 Skater’s nodules/pad23 Skate bite/lace bite23 Malleolar bursitis23 Piezogenic pedal papules22 Baseball pitcher’s friction dermatitis6 Tylomas20 Pump bumps23 Hyperkeratosis and frictional dermatitis from practicing kendo24	-	-	-
B. Soldiers	-	-	-	Friction Blisters25 Corns and Calluses26	-	-	-
C. Musicians	-	Fiddler’s neck16 Clarinettist’s cheilitis27 Flautists chin27 Lip Callosity28	Cellists chest27	Drummer’s digits27 Guitarist’s fingers/Harpist’s fingers27 Garrod’s fingers/Violinists pads27	-	-	-
D. Computer/Electronic device-related	-	-	-	Cell thumb29 Mousing callus30 Writer’ bump29	-	-	-
2. Related to Cultural Practices
A. Frictional Melanosis	-	Facial frictional melanosis31	Davener’s dermatoses32 Lifa disease33 Orphan rocker tracks34 Frictional Dermatosis due to car seat35	Frictional asymptomatic darkening of the extensor surfaces36 Frictional melanosis of rubbing inner thighs37	-	-	-
B. Clothing Related	Nylon cloths friction dermatosis38	-	Induced by sari and petticoat drawstrings18,39,40 Waist dermatoses-sari39	Friction blisters due to socks15	Friction alopecia due to socks7,8	-	-
AC. Religious Practices/ Praying related	-	Prayer’s Nodules18,41	-	Prayer’s Nodules18,41 Pew blisters or ‘prayer blisters’41 Davener’s dermatitis32 Yoga sign42	-	-	-
3. Miscellaneous
	-	Acne mechanica43 Folliculitis mechanica43 Traumatic anserine folliculitis44	-	Amputation stump callosities45	-	Frictional keratosis of oral mucosa or Benign alveolar ridge keratosis3 Morsicatio buccarum and linguarum4 Frictional dermatoses due to sexual practices46,47	Frictional trauma to nails10

Clinical Features [Table 3]

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Figure 3:

Piezogenic pedal papules-associated with figure skaters, runners and weightlifters, due to the high-impact surface collisions which cause herniation of subcutaneous fat into the dermis. Patients generally present with asymptomatic papules over the medial and lateral aspect of heels

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Figure 4:

Callosities: Yellowish, hyperpigmented hyperkeratotic callosities present on the palm and proximal digits in a sportsperson

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Figure 5:

Guitarist’s fingers: These present as calluses at the sides and tips of the fingers

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Figure 6:

Prayer’s nodules: The religious practice of squatting and touching the forehead repeatedly on the ground during prayer by Muslims, leads to formation of nodules or calluses on the forehead

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Primary

Occupational

Frictional dermatoses in sportspersons

Sports entail exposure to several factors such as trauma, prolonged sun exposure, infections and friction, thus increasing the propensity of a variety of skin problems amongst sportspersons. Frictional dermatoses are among the most common cutaneous manifestations in this group.^{6,17,2-24,50-56}

Frictional dermatoses in soldiers

Friction-related skin injuries constitute one of the commonest dermatological conditions reported in military recruits and clinically present as corns, calluses or friction blisters localised to the pressure-bearing sites.^25,26,50

Frictional dermatoses amongst musicians

Musicians are particularly predisposed to develop frictional dermatoses, which typically present at the site of contact with the musical instrument.^16,27,58-60

Computer/electronic devices related frictional dermatoses

This category of frictional dermatoses has emerged in the past few decades due to the rampant use of computer electronics. The manifestations predominate on the users’ hands and fingers.^29,30,61-63

Related to cultural practices

Indigenous cultural practices, religious customs and type of clothing also play a key role in causation of a friction related skin diseases and are especially relevant in the Indian setting.^{7,8,15,18,31-44,64}

Miscellaneous

Certain clinically distinct frictional dermatoses are not specific to any category. Such entities, as well as those that manifest in the mucosa and nails, have been included here [Table 4].^{3,4,10,45-49,65,66}

Table 4: Miscellaneous frictional dermatoses

Entity	Etiopathogenesis	Clinical feature	Diagnosis	Treatment
Face
Acne mechanica43	Localised acne form eruptions due a combination of friction, pressure and occlusion. Sweating causes keratin hydration and decreased size of the pilosebacoeus exit duct, leading to sebum accumulation, creating a favourable condition for bacterial colonisation and inflammation	Comedones, inflammatory papules and pustules; cysts and nodules in severe cases Common in sports persons wearing occlusive protective gear and patients using medical devices such as a prosthesis or crutches	Clinical Allergic contact dermatitis due to substances in the occlusive covering must be ruled out	Removal of the inciting factor Benzoyl peroxide, topical retinoids, keratolytics Topical or systemic antibiotics where necessary22
Traumatic anserine folliculosis44 [Figure 7]	Resting or supporting the head in a particular position leading to repeated friction at the site	Multiple, closely-set, grouped follicular papules (‘anserine’ or goose-like appearance), usually on the chin, jaws or neck	Clinical HPE: hyperkeratosis, hypergranulosis, focal presence or increase of stratum lucidum, rudimentary follicles and dilated follicular opening with retained keratotic material. Mild perivascular inflammatory infiltrate is occasionally seen	Removal of inciting factor
Acanthoma fissuratum (misnomer: Granuloma fissuratum)65 [Figure 8]	Chronic persistent trauma due to ill-fitting spectacle frame or heavy glasses (spectacle frame granuloma) Abnormal anatomy and pre-existing skin disease (atopy, vulvar dermatoses, vaginal candidiasis) may contribute Ill-fitting dentures, tight-fitting underwear, hearing aid, have been implicated at other sites	Pruritic or asymptomatic Usually unilateral; firm, folded coin-shaped lesion, flesh-coloured papule, nodule, or plaque with a central groove dividing the lesion into two halves (Coffee bean appearance) Sites: Retroauricular and superior auricular sulci, bridge of nose (spectacle frame) Labio-alveolar sulcus (ill-fitting dentures) External auditory canal (in-the-canal hearing aids) Shaft of penis (tight underwear) Posterior fourchette of vulva, usually associated with co-existing disease Dyspareunia is common	Clinical: The site correlates with points on the skin/mucosa where the spectacle frame or denture persistently rests or apposes Biopsy may be performed as lesion may simulate BCC HPE: Hyperkeratosis, variable parakeratosis, acanthosis, spongiosis (occasional). Epidermis shows central attenuation corresponding to the longitudinal groove. May be filled with inflammatory cells and keratinous debris. Dermis may show chronic inflammation. Granuloma is absent	Removal of the inciting agent Surgical excision, intralesional corticosteroids, electrosurgery. Treatment of co-existing condition, especially vulval disease which co-exists with lichen sclerosus, or vulvo-vaginal candidiasis66 Perineoplasty may be required for persistent vulval granuloma fissuratum due to dyspareunia and recurrent fissuring66
Limbs
Frictional dermatoses in amputees45	Poorly fitting prostheses	Follicular hyperkeratosis due to friction, usually at weight-bearing sites in the popliteal fossa, inguinal region and distal stump Callus formation and lichenification may also occur	Clinical	Adjustment of prosthesis Topical keratolytics
Frictional dermatoses in oral mucosa
Benign alveolar ridge keratosis3	Chronic frictional trauma due to mastication	White papule or plaque on the keratinised mucosa of the retromolar pad, or edentulous maxillary or mandibular alveolar ridge Males more commonly affected Prevalence highest in the fifth to seventh decades	Clinical HPE: moderate to marked hyperkeratosis, mild surface papillomatosis, acanthosis with wedge shaped hypergranulosis. Focal parakeratosis may be present and basal layer is intact with insignificant mitotic activity and very mild reactive atypia	No intervention required
Morsicatio buccarum and linguarum4	Repetitive habit of rubbing, chewing or sucking of the oral mucosa against teeth leads to frictional keratosis of the buccal mucosa (morsicatio buccarum), tongue mucosa (morsicatio liguarum) and lip.	Ill-defined areas of grey to white papules and plaques, often bilateral. The surface is rough with irregular tags, which results in a cycle of the patient biting the mucosa to remove the rough tags, producing more tags in turn. Erosions and ulcers may be present if the bite trauma is extensive.	HPE: Marked hyperkeratosis and parakeratosis with shaggy or shredded keratin on the surface. Ballooned cells may be seen in the spinous layer. Dysplasia is absent	Reassurance No intervention required
Frictional dermatoses of genitalia due to sexual practices
Frictional trauma to nails10	Repeated abrasion or friction on nail plate Habitual nail picking (Onychotillomania)	Polishing of the nails, causing them to have a shiny appearance Central ridge deformity Various degrees of nail dystrophy	Clinical	Modification of behaviour Use of protective equipment
Frictional dermatoses of genitalia due to sexual practices
Penile coital injury46	Sexual intercourse Risk is greater with increasing age, multiple sexual partners, application of substances (creams, lotions or lubricants) on the penis or vagina. The risk is reduced in circumcised men and with use of condom	Abrasions, cuts and scratches common in young men increases the risk of acquisition of HIV and other STIs, due to disruption of the epithelial barrier	Clinical	Use of condom
Frictional dermatitis of Onan47	Excessive masturbation	Pruritic eruption on the penis. Subacute to chronic eczema and in more chronic cases, lichenification and hyperpigmentation is noted on the penile corona or the shaft, sometimes in linear distribution	Clinical History of appearance of lesions following periods of increased masturbation	Emollients

HPE: Histopathological evaluation, BCC: Basal cell carcinoma

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Figure 7:

Traumatic anserine folliculosis: Characterised by multiple, closely-set, grouped follicular papules (‘anserine’ or goose-like appearance), usually on the chin, jaws or neck in children or adolescents, often with a history of resting or supporting the head in a particular position leading to repeated friction at the site

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Figure 8:

Acanthoma fissuratum: Pruritic or asymptomatic unilateral; firm, folded coin-shaped lesion, flesh-coloured plaque with a central groove dividing the lesion into two halves (Coffee bean appearance) resulting from chronic persistent trauma due to ill-fitting spectacles

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Secondary frictional dermatoses [Table 5]

Table 5: Secondary frictional dermatoses

Secondary frictional dermatoses	Etiopathogenesis	Clinical features	Diagnosis	Treatment
Sweat dermatitis/Frictional sweat dermatitis5,67	Chronic cumulative irritant dermatitis to sweat solutes Controversial role of occlusion and friction	Glazed sharply demarcated erythematous plaques localised to sites of friction Can vary from hyperpigmented ‘parchment-like’ skin to miliaria and maculopapular rash Burning and stinging All ages	Clinical Dermoscopy: variable findings as per clinical morphology HPE: Mild spongiform dermatitis	Avoidance of hot and humid conditions No specific treatment necessary Subsides spontaneously without sequelae in around 2 weeks
Diaper dermatitis68	Repeated contamination of skin by irritant faeces with active enzymes in addition to friction and excessive hydration Thinner epidermis and stratum corneum and immature barrier function in infants	Painful, well-defined erythematous macules ± papules, pustules or erosions on areas in contact with diaper including buttocks, genitals, inner thighs and waistline Sparing of inguinal folds Infants and elderly	Clinical KOH to rule out fungal infection HPE: Mild spongiform dermatitis	Frequent diaper changes Aeration of skin Use of water with gentle cleanser for cleaning followed by application of petrolatum or zinc oxide-based barrier cream Low-potency topical corticosteroids with or without antifungals if non-responsive
Juvenile plantar dermatoses/’sweating sock dermatitis’69	Sweating and friction in conditions of occlusion (prolonged wearing of shoes and socks without aeration) Atopic diathesis	Erythematous, glazed and fissured plaques on plantar surface of forefoot, associated with soreness Spares web spaces and dorsae Young children	Clinical KOH to rule out fungal infection HPE: Subacute or chronic spongiotic dermatitis with peri-eccrine lymphocytic infiltrate	Self-limiting, resolves spontaneously in a few years Wear open sandals Emollients and topical corticosteroids
Frictional lichenoid dermatitis/Dermatitis papulose adultorum/Sutton’s summertime prurigo70 [Figure 9]	UV radiation Friction Atopy	Grouped lichenoid papules over elbows and knees Asymptomatic or pruritic Spring and summer Young children	Clinical HPE: Non-specific. Hyperkeratosis, acanthosis with or without mild spongiosis and perivascular lymphocytic infiltrate	Self-limiting Emollients and mild topical corticosteroids
Frictional dermatitis71	Eczematous process triggered by chronic friction Occupational handling of tools, papers, plastic etc. Co-existence of contact allergy, atopic dermatitis or psoriasis	Dryness and hyperkeratosis on the palm of the dominant hand as well as the sides and tips of fingers Can evolve to painful psoriasiform plaques with or without vesicles and/or fissuring	Clinical Studies on HPE not available, likely spongiotic dermatitis	Removal of precipitating factor (friction) or use of protective equipment Emollients, humectants and keratolytics Topical corticosteroids Grenz ray therapy
Frictional amyloidosis/’Brush amyloidosis’72	Chronic scratching or rubbing	Rippled hyperpigmentation over areas of chronic scratching or rubbing Can be pruritic Commonly on the upper back or lower limbs	Clinical HPE: Hyperkeratosis and acanthosis of epidermis, deposition of amyloid in papillary dermis (pale, homogenous eosinophilic material with fissures)	Avoid scratching Emollients, topical mid-potent corticosteroids, DMSO Ablative lasers

DMSO: Dimethyl sulfoxide, HPE: Histopathological evaluation, KOH: Potassium hydroxide

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Figure 9:

Frictional lichenoid eruption: Presents as grouped lichenoid papules over the elbows and knees in young children during spring and summer months

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As we have already elucidated, entities traditionally classified as primary ‘frictional dermatoses’ are those caused due to the rubbing of one body against another, termed as dry friction. However, friction may be contributory to dermatoses wherein factors such as sweat, moisture or a pre-existing skin disease play a larger role. Friction also plays a pivotal role in many contact dermatoses, by disrupting the stratum corneum barrier.^{19,67-70,72-77}

Differential Diagnosis

Careful history is of paramount importance in diagnosing frictional dermatoses and differentiating it from other clinically similar skin conditions. Differentials vary based on the location of the lesions, that is, skin, mucosa, hair and nail [Tables 6a and 6b].

Diagnosis

The diagnosis of frictional dermatoses is based on a thorough history as well as complete physical examination of the patient. Examination must focus on the type, morphology, distribution and location of lesions. The pattern of involvement provides valuable clues to the probable sources of friction such as sports equipment, musical instruments and cultural practices. The morphology helps establish the cause as well as duration of the insult. Non-invasive modalities such as dermoscopy are a useful diagnostic aid [Figure 10a].^5,7,31,78-81 In addition, patch and photo patch testing may be helpful to rule out contact dermatitis, an important differential. Diagnostic dilemma and differentiation from clinical mimics may warrant a skin biopsy [Figure 10b]. Most of the entities are characterised by lichenification and show hyperkeratosis, acanthosis and elongation of rete ridges. Hypergranulosis accompanying these features is seen in callus or nodule formation.^22,23 Conditions presenting with folliculitis including traumatic anserine folliculitis and acne mechanica reveal dilated follicular infundibulum filled with keratin along with a mild perivascular infiltrate. Foreign-body reaction, with abscess, cyst and granuloma formation can be seen in Fiddler’s neck.^16,41,43 Hyperpigmentation as seen in frictional melanosis, Lifa disease or Davener’s dermatitis correlates histologically with increased basal layer pigmentation and pigment incontinence.^31-33 Friction blisters are characterised by an intraepidermal split without inflammation while eczematous lesions show oedema with intraepidermal neutrophilic and mononuclear infiltrate.^25,57,71

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Figure 10a:

Important dermoscopic features of frictional dermatoses. Most of the entities are characterised by lichenification and show hyperkeratosis, acanthosis and elongation of rete ridges. Hypergranulosis accompanying these features is seen in callus or nodule formation. Conditions presenting with folliculitis including traumatic anserine folliculitis and acne mechanica reveal dilated follicular infundibulum filled with keratin along with a mild perivascular infiltrate. Foreign-body reaction, with abscess, cyst and granuloma formation can be seen in Fiddler’s neck. Hyperpigmentation as seen in frictional melanosis, Lifa disease or Davener's dermatitis correlates histologically with increased basal layer pigmentation and pigment incontinence. Friction blisters are characterised by an intraepidermal split without inflammation while eczematous lesions show oedema with intraepidermal neutrophilic and mononuclear infiltrate

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Figure 10b:

Important histopathological features of frictional dermatoses: Most of the entities are characterised by lichenification and show hyperkeratosis, acanthosis and elongation of rete ridges. Hypergranulosis accompanying these features is seen in callus or nodule formation. Conditions presenting with folliculitis including traumatic anserine folliculitis and acne mechanica reveal dilated follicular infundibulum filled with keratin along with a mild perivascular infiltrate. Foreign-body reaction, with abscess, cyst and granuloma formation can be seen in Fiddler’s neck. Hyperpigmentation as seen in frictional melanosis, Lifa disease or Davener's dermatitis correlates histologically with increased basal layer pigmentation and pigment incontinence. Friction blisters are characterised by an intraepidermal split without inflammation while eczematous lesions show oedema with intraepidermal neutrophilic and mononuclear infiltrate

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Treatment

The principles of treatment include providing symptomatic relief, determining the mechanical aetiology and treating the lesion and preventing further recurrence. Various pressure relieving devices (e.g., footwear with cushioned insoles and silicon sheets lubricants and barrier creams) are effective tools to protect stratum corneum.⁸² The main treatment aims at the removal of triggering habits or contact with external causative agent. Topical agents such as keratolytics and humectants help in decreasing the hyperkeratosis and regulating epidermal proliferation. Various depigmenting agents such as retinoic acid analogues, kojic acid and arbutin help in decreasing hyperpigmentation. Q-switched Nd : YAG (1064 nm and 532 nm) laser has been found to be useful in frictional dermatoses with hyperpigmentation.^27,83 Grenz rays help in decreasing the thickness of skin. A study reported remarkable improvement in patients with frictional hand dermatitis after six sessions, following a weekly dose of 400 rads (4Gy).⁸⁴

Current Times: Mechanical Dermatoses in The Era of COVID-19

In the era of COVID-19 three major types of mechanical dermatoses have been reported, which include device-related pressure injury,^85,86 moisture-associated skin damage and skin tears.^87,88 According to a study done by Jiang et al. the prevalence of device-related pressure injury skin injuries amongst healthcare workers was 30% and this prevalence was reported to be higher as compared to patients using respiratory devices, tubes and splints (2.1–27.9%).⁸⁹

This may be attributed to the prolonged duration of wearing personal protective equipment in combination with sweating and occlusion.

The common locations of device-related pressure injury among the medical personnel were bridge of the nose, ears, cheeks and forehead. Factors such as the pressure induced by the goggles on the bridge of nose and cheeks as well as the ear compression due to the mask strap, pressure on the forehead due to the surgical caps and face shield have been implicated [Figure 11].⁹⁰

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Figure 11:

Mask induced frictional dermatoses over the bridge of the nose

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Sweating leads to moisture-associated skin damage, which causes skin maceration as well as redness, itching, pain and pricking. Sweat-induced skin soaking along with pressure can cause increased friction coefficient between the personal protective equipment and skin; thus, when the mask and goggles are removed quickly, it can lead to skin tears. The factors associated with increased skin tears on logistic regression analysis by Jiang et al., were grade of personal protective equipment, heavy sweating, daily wearing time and male gender.⁸⁹ Bhoyrul et al., found a higher incidence of folliculitis/acne and occlusion and frictional dermatoses, when compared to glove related reactions.¹¹ Rustemeyer et al., also found that tight fitting equipment induced pressure and friction could culminate in acne mechanica due to rupture of microcomedones.⁹¹ The authors suggested avoiding tight-fitting headgear and facemasks and recommended regular washing and cleansing to help improve this condition. In regard to dermatoses due to skin friction, mechanical factors including material and repetitive forces when wearing personal protective equipment can lead to occupational and frictional dermatoses.⁹¹ The recommendations are to use materials with less shearing forces which are more breathable and comfortable. Furthermore, non-glove personal protective equipment specially footwear provides ideal environment for the growth of human papilloma virus since the moist environment and frictional forces associated with it increase the risk of abrasions and thus entry of human papilloma virus, causing warts.¹¹

Taking frequent breaks and removing excess sweat may facilitate alleviation of frictional dermatoses related to protective gear. Adequate hydration and regular use of emollients are essential to maintain barrier integrity and it is recommended that moisturisers should be used at least half an hour before wearing the mask. Low potency topical steroids or tacrolimus may be necessary in cases which fail to respond to conservative therapy.⁹²

Conclusion

Frictional dermatoses may be defined as ‘a group of disorders caused by repetitive trauma to the skin as a result of friction of varying aetiology, which can have a wide range of cutaneous manifestations depending on the type of insult.’

The susceptibility of an individual’s skin to friction differs and is influenced by factors both extraneous and inherent. The manifestation of friction related skin injury depends on the type of friction, intensity of the force and the nature of the surface and can clinically present as lichenification, hyperpigmentation, erythema, scaling, fissuring, blisters, ulceration and chronic alterations. We have devised a simple classification based on morphology, histopathological characteristics, anatomical region affected and the major predisposing factors such as the occupation. In the current era of COVID-19, three major types of mechanical dermatoses including device-related pressure injury, moisture-associated skin damage and skin tears have been described.

The diagnosis of frictional dermatoses is based on a detailed history and examination where the pattern of involvement provides valuable clues to the probable sources of friction and morphology helps establish the cause as well duration of the insult. The principles of treatment include providing symptomatic relief, determining the mechanical aetiology, treating the lesion and preventing further recurrence.