2.  It is a common disorder,autosomal dominant
 Seen in childhood and reaches its peak incidence
in adolescence.
 keratinous plugs in the follicular orifices with
varying degrees of perifollicular
erythema.

3. Clinical Picture:
 The lesions appear as small gray to white plugs of
keratin that obstruct the mouths of the follicles
entrapping the hair.
 sites of predilection: extensor surfaces of
the upper arms, thighs & buttocks.
 except glabrous skin (like the palms
or soles of feet)

4.  Treatments: may consist of moisturizing or
keratolytic treatments including: urea,
lactic acid, salicylic acid, or topical retinoids.

5.  a disease of abnormal keratinization
 appears in childhood.
 The skin lesion presents with grouped follicular
papules occluded by a projecting keratinous spine.
 Sites:extensor surface of the extremities,
thighs and abdomen.
 DD: lichen planus ,seborrheic dermatitis.

6.  Its chronic thickening of palms and soles.
 may be inherited (hereditary) or, more
commonly, acquired.
 Hereditary keratoderma : runs in families, its Ad
or AR
 Acquired keratoderma: occurs as a result of a
change in the health or environment

7.  The genetic basis involves mutations in
genes encoding
 keratins,
 connexins, and
 desmosomal components.

8. Clinically, three distinct pattern :
1. Diffuse type : the whole palm and sole,
2. focal type : are restricted to more limited
areas(mainly affect pressure areas)
3. punctate type : are bead-like tiny lesions

10. Complications:
 severe pain, difficulty in walking, and
secondary infection.
 Treatments: keratolytics and systemic
retinoids
appropriate footwear is helpful.

11. Different skin diseases may give rise to
palmoplanter hyperkeratosis
 Psoriasis. Hyperkeratosis of the palms and soles
with the silvery scales.
 Reiter‘s disease
 Pityriasis rubra pilaris..
 Eczema

12.  Lichen planus
 Viral warts in immuno-compromised patients
may be confluent on the palms or soles.
 Hyperkeratosis due to dermatophytes (fungal
skin infections).
 Syphilis.
 Arsenic ingestion: causes multiple, irregular
warty keratoses