Trichology- Pityriasis Amiantacea

Pityriasis amiantacea (also known as “Tinea amiantacea”) is an eczematous condition of the scalp in which thick tenaciously adherent scale infiltrates and surrounds the base of a group of scalp hairs. It does not result in scarring or alopecia.

Jean-Louis-Marc Alibert in 1832 first described pityriasis amiantacea as “la porrigine amiantace’e” because its scales reminded him of the mica-like substance observed in young birds. Since then, several names including tinea amintacea, asbestos scalp, tinea asbestina, or keratosis follicularis amiantacea have been used to describe pityriasis amiantacea 7).

Pityriasis amiantacea is typically considered to be a reactive condition to several inflammatory diseases rather than a specific diagnosis. Common conditions that may present with pityriasis amiantacea include 8):

  • Scalp psoriasis
  • Seborrheic dermatitis
  • Atopic dermatitis
  • Tinea capitis.

Head lice and lichen simplex should also be considered. Pityriasis amiantacea may also be observed as a sequel or complication of streptococcal infection and lichen simplex 9).

When no underlying cause is found, the condition is often called idiopathic pityriasis amiantacea.

Some authors suggest that pityriasis amiantacea is a possible complication in infants with seborrheic dermatitis 10). Others are emphatic in pointing out that the reaction is more common among children although it can occur at any age 11). The prospective study of 85 pityriasis amiantacea cases revealed a mean age diagnosis of 23.8 years in the interval ranging from 5 to 63 – thus encompassing children and adolescents, with a female predominance 12). In this study 13), psoriasis accounted for 35.3% of the cases; aggregated seborrheic dermatitis and atopic eczema for 34.2%; tinea capitis – diagnosed by mycological examination – for 12.9% of cases.

Figure 1. Pityriasis amiantacea (scalp psoriasis)

scalp psoriasis pityriasis amiantacea

Footnote: Focal masses of thick, adherent, asbestos like yellow brown scales over fronto-parietal and vertex region of scalp.

Figure 2. Pityriasis amiantacea (tinea capitis)

tinea capitis pityriasis amiantacea

Footnote: Physical examination shows thick, whitish, asbestos-like scales surrounding and binding the hair on the right parietal region of the scalp (better visible in the box) (a). Polarized light dermoscopic examination displays white scales and compact white keratotic material adhering to tufts of hair (asbestos-like scaling) without erythema; “question mark” (black arrow in the box) and “zigzag” (hair shaft bent at more than one point—black arrowhead in the box) hairs are also visible (b).

[Source 15) ]

Is pityriasis amiantacea contagious?

It depends on the underlying cause of pityriasis amiantacea. Pityriasis amiantacea is a reaction pattern rather than a specific diagnosis. Common conditions that may present with pityriasis amiantacea include:

  • Scalp psoriasis
  • Seborrheic dermatitis
  • Atopic dermatitis
  • Tinea capitis.

Head lice and lichen simplex should also be considered. Pityriasis amiantacea may also be observed as a sequel or complication of streptococcal infection and lichen simplex 16).

When no underlying cause is found, the condition is often called idiopathic pityriasis amiantacea.

Microorganisms’ role in pityriasis amiantacea development has been debated. Staphylococci are isolated as colonizers in up to 97% of the pityriasis amiantacea patients, more commonly Staphylococcus aureus, followed by coagulase-negative staphylococci and micrococci 17). In addition, diverse species of fungus, including Microsporum canis, Trichophyton violaceum, Trichophyton rubrum, Trichophyton schoenleinii, and Trichophyton verrucosum, have been demonstrated in some reports 18). These microorganisms could be also implicated in the maintenance of the disease, producing epidermal cell differentiation inhibitors, leading to perpetuate the disease 19). Thus, the use of antibiotics plays a fundamental role in the treatment and/or prevention of pityriasis amiantacea recurrences 20). The most commonly used antibiotic is ketoconazole 2% shampoo and oral griseofulvin (10 mg/kg). These medications have been associated with removal of scales after 2–3 months of treatment 21).

In addition to the antimicrobial therapy, patients with pityriasis amiantacea require topical oil-based products to facilitate the removal of the thick scales and crusts. Salicylic acid 5%–10% ointment is the most commonly employed. In severe cases, high-potency topical corticosteroids are beneficial (betamethasone dipropionate 0.1% solution) 22). In extensive and persistent disease, topical and oral retinoids are usually necessary taking precautions because of their teratogenicity 23).

Pityriasis amiantacea causes

Pityriasis amiantacea is a reaction pattern rather than a specific diagnosis. Common conditions that may present with pityriasis amiantacea include:

  • Scalp psoriasis
  • Seborrheic dermatitis
  • Atopic dermatitis
  • Tinea capitis.

Head lice and lichen simplex should also be considered. Pityriasis amiantacea may also be observed as a sequel or complication of streptococcal infection and lichen simplex 24).

When no underlying cause is found, the condition is often called idiopathic pityriasis amiantacea.

Several factors have been implicated in pityriasis amiantacea development such as drugs, anxiety, and abrupt changes in the environmental conditions 25). Some descriptive data support a probable participation of tumor necrosis factor-alpha (TNF-α) and interferon-α in the pathogenesis of pityriasis amiantacea 26). In patients with Crohn’s disease treated with TNF-α inhibitors, a stimulation of alternative pro-inflammatory pathways, including up-regulation of the IL-1 family, potential generation of autoreactive T cells, and keratinocyte proliferation, was observed 27).

Other medications associated with the development of pityriasis amiantacea include the inhibitor of the mutated BRAF gene (vemurafenib) for melanoma 28). A careful understanding of these drug reactions could provide insights to prevent the development of pityriasis amiantacea lesions and also to allow an early diagnosis and management. However, one must keep in mind that cutaneous adverse effects can appear with variable time lapse. In case studies, the authors observed that pityriasis amiantacea was triggered after the use of valproic acid, a glycogen synthase kinase-3β (GSK-3β) inhibitor that stabilizes cytoplasmic β-catenin and facilitates the activation of the Wnt/β-catenin pathway 29). Valproic acid was started to manage a chronic epileptic disorder. Valproic acid GSK-3β inhibition promotes keratinocyte growth, especially in hair follicles, where its participation is critical for enhancing the proliferative activity of the dermal papilla and promoting the elongation of the hair shaft 30). This proliferative capacity has made valproic acid a candidate for the treatment of alopecia 31). Indirectly, valproic acid is also able to induce alkaline phosphatase similar to minoxidil 32). In addition, valproic acid also induces growth factors such as insulin-like growth factor-1, fibroblast growth factor-10, and the follicular stem cell markers keratin-15 and CD34 33). However, because of the rarity of pityriasis amiantacea, no cases of the association of pityriasis amiantacea with valproic acid have been published 34).

Microorganisms’ role in pityriasis amiantacea development has been debated. Staphylococci are isolated as colonizers in up to 97% of the pityriasis amiantacea patients, more commonly Staphylococcus aureus, followed by coagulase-negative staphylococci and micrococci 35). In addition, diverse species of fungus, including Microsporum canis, Trichophyton violaceum, Trichophyton rubrum, Trichophyton schoenleinii, and Trichophyton verrucosum, have been demonstrated in some reports 36). These microorganisms could be also implicated in the maintenance of the disease, producing epidermal cell differentiation inhibitors, leading to perpetuate the disease 37). Thus, the use of antibiotics plays a fundamental role in the treatment and/or prevention of pityriasis amiantacea recurrences 38). The most commonly used antibiotic is ketoconazole 2% shampoo and oral griseofulvin (10 mg/kg). These medications have been associated with removal of scales after 2–3 months of treatment 39).

In addition to the antimicrobial therapy, patients with pityriasis amiantacea require topical oil-based products to facilitate removal of the thick scales and crusts. Salicylic acid 5%–10% ointment is the most commonly employed. In severe cases, high-potency topical corticosteroids are beneficial (betamethasone dipropionate 0.1% solution) 40). In extensive and persistent disease, topical and oral retinoids are usually necessary taking precautions because of their teratogenicity 41).

Table 1. Identifying the cause of pityriasis amiantacea

Skin condition Description
Psoriasis Well-defined red scaly plaques on elbows and knees (chronic plaque psoriasis)
Red shiny patches in skin folds (flexural psoriasis)
Nail pitting, yellowing or thickening due to nail psoriasis
Psoriatic arthritis
Seborrheic dermatitis Patches similar to psoriasis but less well-defined and less red
Scale tends to be yellowish in color
Affects eyebrows, nasal crease, behind the ears and chest
Atopic dermatitis Usually starts in infancy
Skin folds of arms and legs often affected
May have generally itchy dry skin
Flare-ups result in red, blistered, scratched patches
Tinea capitis Fungal culture reveals dermatophyte fungus
Localized scaly bald patches
Broken off or loose hairs
There may be cervical lymph node enlargement
Head lice Egg cases on hair shaft (nits) and scurrying lice
Prominent on back of neck and behind ears
There may be cervical lymph node enlargement
Lichen simplex Localized itchy dry patch of skin
Often at back or one side of scalp
Thickened, darkened plaques with broken-off hairs due to scratching

Pityriasis amiantacea differential diagnosis

Pityriasis amiantacea differential diagnosis include:

  • Scalp psoriasis
  • Seborrheic dermatitis
  • Atopic dermatitis
  • Tinea capitis

Other concretions around the hair shaft:

  • White piedra – many soft, fluffy white or light brown nodules are seen; more commonly affects pubic hair, axillary hair, beard and mustache area. Scalp is occasionally involved.
  • Black piedra – usually affects scalp hair. Small compact black nodular concretions, often multiple on one hair, are seen.
  • Trichomycosis axillaris – long, thin yellow or orange concretions may spiral around hair shafts of axillary or pubic hair.
  • Nits (head lice) – nits adhere to the proximal portions of affected hair. They are small and white. Associated adult lice attach to any portion of the hair shaft.

Pityriasis amiantacea prevention

Pityriasis amiantacea is a reaction pattern rather than a specific diagnosis. Common conditions that may present with pityriasis amiantacea include:

  • Scalp psoriasis
  • Seborrheic dermatitis
  • Atopic dermatitis
  • Tinea capitis.

Head lice and lichen simplex should also be considered.

When no underlying cause is found, the condition is often called idiopathic pityriasis amiantacea.

Therefore, pityriasis amiantacea cannot be prevented.

Pityriasis amiantacea signs and symptoms

Pityriasis amiantacea is characterized by thick scales wrapping around and binding down tufts of hair. The scaling may be localized or generalized depending on the underlying condition and its duration.

Pityriasis amiantacea may be complicated by secondary staphylococccal infection (impetiginization), when the skin becomes sticky, oozy and crusted. Temporary or permanent hair loss (alopecia) may also occur.

If the underlying skin condition is not clear, the entire skin should be examined to uncover the cause of pityriasis amiantacea. This enables targeted therapy against the specific disease and prevents long term complications such as permanently bald areas.

Pityriasis amiantacea diagnosis

Skin and hair samples for mycology and bacterial culture may be useful. Skin biopsy is rarely necessary.

Pityriasis amiantacea treatment

Pityriasis amiantacea treatment depends on the specific underlying disease.

  • Mineral or vegetable oils especially olive oil may help to loosen the adherent scales.
  • Washable leave-on creams or wash-off shampoos containing salicylic acid, coal tar and sulphur may be of help in reducing the scaling and inflammation, e.g. coconut compound ointment.
  • Intermittent courses of topical steroids are useful for psoriasis and various types of dermatitis, often as lotions or gels.
  • Antifungal shampoo (e.g. ketoconazole or ciclopirox) is often prescribed and may be helpful for underlying seborrhoeic dermatitis.
  • Oral antifungal agents are necessary for confirmed tinea capitis infection.
  • Oral antibiotics may be prescribed for bacterial infection.

Idiopathic pityriasis amiantacea often clears completely with treatment and does not recur. Tinea capitis may be cured by appropriate antifungal treatments. However, pityriasis amiantacea or less severe scalp scaling tends to persist or reappear when it is due to a chronic skin condition such as psoriasis or seborrhoeic dermatitis.

 

See the source image

Pityriasis Amiantacea-
63 patients of both sexes with pityriasis sicca or steatoides were examined for the presence of Pityrosporum ovale on the scalp. Only those cases in which very numerous yeasts were seen in all squamae present in the preparation were considered positive. According to the severity or duration of pityriasis, 60% of the patients in this population represented severe cases and 38% refractory cases.
A solution of econazole nitrate was applied as a spray, morning and evening, for a period of 10 to 20 days (mean). The overall assessment of the clinical effects of econazole nitrate indicated 56 favorable results, with complete disappearance of objective clinical signs in 47 cases; the course of pruritus proceeded roughly parallel with that of the objective signs.
The mycological checking of the clinical results, performed at least 7 days after the conclusion of therapy, disclosed 6 failures and 57 successes. In 17 patients, the microscopic examination of squamae was complemented by culture before and after treatment: in all cases, the culture, positive before econazole nitrate therapy, became negative after the treatment, thus confirming the results of direct examination. These data suggest that Pityrosporum ovale plays a pathogenetic part in pityriasis simplex capitis.

Image result for Pityriasis Amiantacea-. Size: 222 x 160. Source: www.solenttrichologyclinic.co.uk

Psoriasis often begins on the scalp or elbows with circular areas of uniform darker/ redder skin clearly differing in color from adjacent normal colored skin.

These areas are covered with dry white, adherent silvery scales, which can sometimes be quite dense. These scales are not easily removed but when they are, then coarse lined skin with bleeding points can be seen underneath them.

Other areas that can be affected are the knees, elbows and shins. The fingernails and toenails can be affected with thimble pitting. Stiff and painful joints can accompany psoriasis.

The cause of psoriasis is unknown, but there would seem to be a familial trait. Two per cent of Caucasians suffer from the condition, which more commonly appears between the ages of ten and thirty.

The condition is triggered by stress, skin damage, illness and bacterial infection. Itching to an adjacent area often denotes an extension of the condition.

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