49: Keratosis Pilaris and Other Follicular Keratotic Disorders

Question 1

What is the likely diagnosis for a 10-year-old child with keratotic follicular papules on the extensor arms and buttocks that worsen in winter?

Answer 1

The likely diagnosis is keratosis pilaris (KP).

Environmental factors such as low ambient humidity during winter can exacerbate the condition.

Question 2

What is the likely diagnosis for a young adult male with hyperpigmentation, erythema, and follicular papules on the preauricular and maxillary areas?

Answer 2

The likely diagnosis is erythromelanosis follicularis faciei et colli (EFFC).

It is most commonly seen in adolescents and young adult males, particularly those with darker skin types.

Question 3

What genetic mutation might be implicated in a patient with ichthyosis vulgaris presenting with keratotic follicular papules and perifollicular erythema?

Answer 3

Mutations in the FLG gene, which cause ichthyosis vulgaris, may be implicated in the follicular hyperkeratosis seen in keratosis pilaris (KP).

Question 4

What environmental factor likely contributes to the improvement of keratosis pilaris (KP) during the summer?

Answer 4

Increased ambient humidity during the summer likely contributes to the improvement in keratosis pilaris (KP).

Question 5

What areas are typically affected in keratosis pilaris rubra (KPR)?

Answer 5

KPR typically affects the cheeks, forehead, and neck.

Question 6

What demographic is most commonly affected by keratosis pilaris (KP)?

Answer 6

Keratosis pilaris (KP) is most common in children and can improve by late adolescence, although it often persists.

Question 7

What dermoscopic findings might be observed in a patient with keratosis pilaris (KP)?

Answer 7

Dermoscopy may reveal thin, short hair shafts that are coiled or twisted within the follicular ostia.

Question 8

What associated conditions might increase the prevalence of keratosis pilaris (KP)?

Answer 8

Associated conditions include ichthyosis vulgaris, atopic dermatitis, hypothyroidism, Cushing syndrome, insulin-dependent diabetes mellitus, obesity, high BMI, Down syndrome, Noonan syndrome, and cardiofaciocutaneous syndrome.

Question 9

What is the typical age of onset for keratosis pilaris (KP)?

Answer 9

Keratosis pilaris (KP) is common in children and can improve by late adolescence, although it often persists.

Question 10

How do the lesions of keratosis pilaris (KP) typically distribute in younger children versus adolescents and adults?

Answer 10

In younger children, lesions typically affect the face and arms, while in adolescents and adults, they are more common on the extensor arms and legs.

Question 11

What are the common clinical features of keratosis pilaris (KP) and how do they vary by age group?

Answer 11

• Primary lesions: Small (typically 1-mm), keratotic, follicular papules with varying degrees of perifollicular erythema.
• Affected areas:
  
  • Younger children: face and arms
  • Adolescents and adults: extensor arms and legs
• Environmental factors: KP is likely accentuated by ambient humidity, with many experiencing improvement during summer months compared to winter.

Question 12

What are the distinguishing features of keratosis pilaris rubra (KPR) compared to typical keratosis pilaris?

Answer 12

• KPR features:
  
  • Erythema is markedly noticeable, extending beyond the perifollicular skin.
  • Limited to cheeks, forehead, and neck.
• Comparison: While typical KP may present with mild erythema, KPR shows significant erythema and is more localized to specific facial areas.

Question 13

What are the potential etiological factors contributing to the development of keratosis pilaris and its variants?

Answer 13

• Etiological factors:
  
  • Defective keratinization of the follicular epithelium.
  • Mutations in FLG (filaggrin gene).
  • Conditions such as hyperandrogenism, insulin resistance, and other genetic or metabolic abnormalities.
  • Follicular plugging due to sebaceous etiology.
• Associated conditions: Higher prevalence in individuals with ichthyosis vulgaris, atopic dermatitis, and other syndromes.

Question 14

What is the clinical significance of erythromelanosis follicularis faciei et colli (EFFC) in relation to keratosis pilaris?

Answer 14

• EFFC features:
  
  • Characterized by hyperpigmentation in addition to erythema and follicular papules.
  • Typically involves the preauricular and maxillary areas, often spreading to the temples and sides of the neck.
• Clinical significance: EFFC is seen primarily in adolescents and young adults, particularly in darker skin types, indicating a potential need for tailored management strategies due to its distinct presentation and associated pigmentation changes.

Question 15

What specific types of lasers might improve associated erythema or hyperpigmentation in keratosis pilaris (KP)?

Answer 15

Vascular- or pigment-specific lasers may modestly improve the erythema or hyperpigmentation associated with keratosis pilaris (KP).

Question 16

What is the inheritance pattern of keratosis pilaris atrophicans (KPA)?

Answer 16

The inheritance pattern of keratosis pilaris atrophicans (KPA) is autosomal dominant.

Question 17

What is the diagnosis for a child with erythema and keratotic follicular papules on the lateral third of the eyebrows, progressing to alopecia, and what is the prognosis?

Answer 17

The diagnosis is ulerythema ophryogenes (UO).

The condition progresses through childhood, leading to permanent alopecia, but progression usually ceases after puberty.

Question 18

What is the specific subtype of keratosis pilaris atrophicans (KPA) that presents with erythema and follicular plugging on the cheeks, progressing to reticular, atrophic scarring, and what is its hallmark feature?

Answer 18

The specific subtype is atrophoderma vermiculatum (AV).

Its hallmark feature is reticular, atrophic scarring that gives a ‘worm-eaten’ or ‘honeycomb’ appearance.

Question 19

What additional treatment option could be considered for a patient with keratosis pilaris (KP) who experiences limited improvement with keratolytic preparations?

Answer 19

Topical retinoids may be considered if keratolytic preparations are not helpful, although they may aggravate associated erythema.

Question 20

What histopathologic findings are associated with keratosis pilaris (KP)?

Answer 20

Histopathologic findings include varying degrees of follicular hyperkeratosis, dilatation of upper dermal vessels, perivascular lymphocytic inflammation, and atrophy or absence of sweat glands.

Question 21

What types of skin care products should be avoided by a patient with keratosis pilaris (KP)?

Answer 21

Drying or irritating skin care products should be avoided to manage keratosis pilaris (KP).

Question 22

What keratolytic preparations might be used for the treatment of keratosis pilaris (KP)?

Answer 22

Keratolytic preparations containing urea, lactic acid, or salicylic acid may be used to soften and smooth keratosis pilaris (KP).

Question 23

What is the prognosis for a patient with keratosis pilaris atrophicans (KPA)?

Answer 23

The condition progresses through childhood, leading to permanent sequelae, but progression usually ceases after puberty.

Question 24

What topical treatment might be used to calm irritation and itch in a patient with keratosis pilaris (KP)?

Answer 24

Short courses of low-potency topical corticosteroids may be used to calm irritation and itch associated with keratosis pilaris (KP).

Question 25

What is the primary goal of treatment for keratosis pilaris (KP)?

Answer 25

The primary goal of treatment is to address the rough texture of the skin.

Question 26

What is the typical prognosis for keratosis pilaris (KP)?

Answer 26

Keratosis pilaris (KP) can improve by adolescence or early childhood, but it persists into later adult life in one-third of patients.

Question 27

What are the key clinical features of ulerythema ophryogenes (UO) and its progression?

Answer 27

- Affects the eyebrows, starting in infancy with erythema and small keratotic follicular papules. - Progresses through childhood, leading to alopecia in the eyebrows. - Progression usually ceases after puberty, but sequelae are permanent. - Involvement of cheeks and forehead can occur, while scalp and eyelash hair remain normal. - Frequently associated with typical keratosis pilaris (KP) affecting arms, legs, or more generalized distribution.

Question 28

What are the management options for keratosis pilaris (KP) and their effectiveness?

Answer 28

- **Avoidance of irritants**: Simple steps like avoiding drying or irritating skin care products and using bland emollients are reasonable first steps. - **Keratolytic preparations**: Urea, lactic acid, or salicylic acid may soften and smooth KP; topical retinoids can be tried but may aggravate erythema. - **Topical corticosteroids**: Short courses can calm irritation and itch but do not improve keratotic plugging. - **Laser treatment**: Vascular or pigment-specific lasers modestly improve erythema or hyperpigmentation associated with KP.

Question 29

What are the characteristics and inheritance patterns of atrophoderma vermiculatum (AV)?

Answer 29

- Usually starts in childhood, between ages 5 and 12, but later onset is possible. - The condition is sporadic, with some familial cases suggesting autosomal dominant inheritance. - An autosomal recessive form with overlapping features of AV and KFSD has been reported in consanguineous families. - Clinical features include erythema and follicular plugging on cheeks, leading to reticular, atrophic scarring (honeycomb appearance). - Alopecia is not a feature of AV, but sparse open and closed comedones and milia may be present.

Question 30

What are the associations of keratosis pilaris atrophicans (KPA) with other syndromes?

Answer 30

- Keratosis pilaris (KP) and ulerythema ophryogenes (UO) are strongly associated with Noonan syndrome (NS) and Cardio-facio-cutaneous (CFC) syndrome. - Over 80% of genetically confirmed CFC patients have KP, and 90% have UO.

Question 31

What is the typical onset age for keratosis pilaris (KP) and ulerythema ophryogenes (UO)?

Answer 31

The typical onset age is 12, but later onset is possible.

Question 32

What inheritance pattern has been suggested for keratosis pilaris (KP) and ulerythema ophryogenes (UO)?

Answer 32

The condition is sporadic; autosomal dominant inheritance has been suggested in some cases.

Question 33

What are the associated skin features of keratosis pilaris (KP) and ulerythema ophryogenes (UO)?

Answer 33

Associated with erythema and follicular plugging on cheeks, progressing to reticular, atrophic scarring (honeycomb appearance).

Question 34

Is alopecia a feature of keratosis pilaris (KP)?

Answer 34

Alopecia is not a feature, but sparse open and closed comedones and milia may be present.

Question 35

What syndromes are strongly associated with keratosis pilaris (KP) and ulerythema ophryogenes (UO)?

Answer 35

KP and UO are strongly associated with Noonan syndrome (NS) and Cardio-facio-cutaneous (CFC) syndrome.

Question 36

What percentage of genetically confirmed CFC patients have keratosis pilaris (KP) and ulerythema ophryogenes (UO)?

Answer 36

Over 80% of genetically confirmed CFC patients have KP, and 90% have UO.

Question 37

What is the association between Noonan syndrome and keratosis pilaris (KP)?

Answer 37

Noonan syndrome is strongly associated with keratosis pilaris (KP) and ulerythema ophryogenes (UO).

Question 38

What is the diagnosis for a patient with progressive scarring alopecia and spiny lesions on the scalp?

Answer 38

The diagnosis is keratosis follicularis spinulosa decalvans (KFSD).

Question 39

What is the inheritance pattern of keratosis follicularis spinulosa decalvans (KFSD)?

Answer 39

The inheritance pattern is X-linked, with males being fully affected and females showing variable expression.

Question 40

What genetic mutations are associated with cardiofaciocutaneous syndrome (CFC)?

Answer 40

CFC is caused by activating mutations in the BRAF, KRAS, MAP2K1, and MAP2K2 genes.

Question 41

What histologic findings support the diagnosis of keratosis follicularis spinulosa decalvans (KFSD)?

Answer 41

Histologic findings include follicular hyperkeratosis, atrophy of pilosebaceous units, perifollicular and perivascular inflammation, and perifollicular fibrosis.

Question 42

What ocular findings might be present in a patient with keratosis follicularis spinulosa decalvans (KFSD)?

Answer 42

Ocular findings may include photophobia, punctate corneal epithelial defects, corneal dystrophy, and blepharitis.

Question 43

What is the hallmark feature of keratosis follicularis spinulosa decalvans (KFSD)?

Answer 43

The hallmark feature of KFSD is progressive scarring alopecia.

Question 44

How does keratosis follicularis spinulosa decalvans (KFSD) differ from IFAP syndrome?

Answer 44

KFSD is characterized by progressive scarring alopecia, which is less severe than IFAP. IFAP presents with congenital atrichia and photophobia.

Question 45

What is the significance of the Ras-MAPK pathway in Noonan syndrome (NS) and cardiofaciocutaneous syndrome (CFC)?

Answer 45

The Ras-MAPK pathway regulates the cell cycle, cellular growth, differentiation, and senescence, with mutations leading to NS and CFC.

Question 46

What are the recommended management options for keratosis follicularis spinulosa decalvans (KFSD) and IFAP syndrome?

Answer 46

Management options include topical corticosteroids or calcineurin inhibitors, keratolytics or retinoids, oral isotretinoin for severe cases, and pulse-dye laser therapy.

Question 47

How does the inheritance pattern affect clinical presentation in males versus females for KFSD and IFAP syndrome?

Answer 47

Both KFSD and IFAP are X-linked disorders. Males are fully affected, while females exhibit variable expression.

Question 48

What areas are typically affected by hair loss in IFAP syndrome?

Answer 48

Hair loss typically involves the scalp, eyebrows, eyelashes, and body hair.

Question 49

What is the likely diagnosis for spiny, folliculocentric papules on the central face in an immunocompromised patient?

Answer 49

The likely diagnosis is trichodysplasia spinulosa (TS).

Question 50

What genetic mutation confirms the diagnosis of IFAP syndrome?

Answer 50

A pathogenic mutation in the MBTPS2 gene confirms the diagnosis of IFAP syndrome.

Question 51

What histopathologic finding is distinct for trichodysplasia spinulosa (TS)?

Answer 51

A distinct histopathologic finding for TS is a hypertrophic hair bulb with an expanded inner root sheath containing numerous eosinophilic trichohyaline granules.

Question 52

What is the texture of the skin in IFAP syndrome?

Answer 52

The skin has a rough, 'nutmeg-grater' texture due to the spiny follicular projections.

Question 53

What microscopic finding is characteristic of trichodysplasia spinulosa (TS)?

Answer 53

Microscopic examination shows thick concretions of inner root sheath material surrounding a poorly formed hair shaft.

Question 54

What causes leonine facies in trichodysplasia spinulosa (TS)?

Answer 54

Leonine facies is caused by thickened skin and distortion of normal facial features due to folliculocentric papules.

Question 55

What long-term morbidity is associated with ocular disease in IFAP syndrome?

Answer 55

Much of the long-term morbidity in IFAP syndrome is associated with ocular disease, including photophobia and corneal defects.

Question 56

What is the typical distribution of lesions in trichodysplasia spinulosa (TS)?

Answer 56

Lesions typically affect the central face, including the nose and forehead.

Question 57

What are the key clinical features of Folliculitis Spinulosa De Calvans?

Answer 57

Folliculitis Spinulosa De Calvans is characterized by persistent pustule formation on the scalp, more severe inflammation, and progressive alopecia after puberty.

Question 58

What are the diagnostic criteria for IFAP syndrome?

Answer 58

Diagnosis is suspected with the triad of follicular keratosis, alopecia or atrichia, and photophobia.

Question 59

What is the clinical significance of trichodysplasia spinulosa in immunocompromised patients?

Answer 59

Trichodysplasia spinulosa presents as folliculocentric papules and can lead to significant skin changes, often occurring in organ transplant patients.

Question 60

What is the pathogenesis of trichodysplasia spinulosa related to immune compromise?

Answer 60

Trichodysplasia spinulosa is caused by the trichodysplasia spinulosa-associated polyomavirus (TSPyV), which infects the inner root sheath of hair follicles.

Question 61

What diagnostic method can confirm the presence of TSPyV in a patient with TS?

Answer 61

The presence of TSPyV can be confirmed by electron microscopy or polymerase chain reaction (PCR) studies.

Question 62

What is the expected clinical course for patients with TS as immune function is restored?

Answer 62

Clinical findings of TS gradually improve and resolve as immune function is restored.

Question 63

What typical treatments for follicular keratosis are ineffective for TS?

Answer 63

Typical treatments such as emollients, humectants, and retinoids are not effective for TS.

Question 64

What antiviral therapies are associated with improvement in TS?

Answer 64

Antiviral therapy with topical cidofovir or systemic valacyclovir is associated with improvement in TS.