Keratosis Pilaris (cont.)
What causes KP?
The exact cause of KP is unknown. There seems to be a problem
with overproduction of the keratin part of the skin called hyperkeratinization.
KP is thought to be partly inherited (genetic) in origin. About 50%-70% of
patients with KP have a known genetic predisposition and a high rate of affected
family members. Many individuals have a strong family history of KP or "chicken
skin." The underlying cause may partly be related to hypersensitivity reactions
and overall dryness of the skin. KP is also closely related to ichthyosis
vulgaris, dry skin, allergies, seasonal allergies, rhinitis, asthma, eczema, and
atopic dermatitis.
The bumps in KP seem to arise from the
excessive accumulation of keratin (very small, dry skin particles) at the
opening of individual hair follicles. The skin as examined under the microscope
demonstrates mild thickening, hyperkeratosis, and plugging of the hair follicle.
The upper skin layers may have some dilation of the small superficial blood
vessels, thereby giving the skin a red or flushed appearance.
How is keratosis pilaris diagnosed?
The diagnosis of KP is very
straightforward and based on a typical skin appearance in areas like the upper
arms. A family history of KP is also very helpful since there is a strong
genetic component to the condition. The diagnosis is confirmed by the
physician's clinical exam.
What else could it be?
Other medical conditions can mimic KP. KP may resemble
acne, milia, folliculitis, eczema, atopic dermatitis, facial rosacea, or dry
skin (xerosis). KP may also resemble uncommon skin conditions like lichen
spinulosus, pityriasis rubra pilaris, phrynoderma (vitamin A deficiency),
ulerythema ophryogenes, ichthyosis vulgaris, eruptive vellus hair cysts,
keratosis follicularis (Darier disease), Kyrle disease, lichen nitidus, lichen
spinulosus, perforating folliculitis, and trichostasis spinulosa.
In India and other countries, a specific condition called erythromelanosis follicularis faciei et colli occurs. This unusual condition has a possible
genetic relationship to KP. Erythromelanosis follicularis faciei et colli is
characterized by the triad of hyperpigmentation (darker skin color), follicular
plugging (blocked hair follicles), and redness of the face and neck.
Are there any lab tests to help diagnose keratosis pilaris?
No specific
laboratory tests aid in the diagnosis of KP. Imaging studies like X-rays and CT
scans are not useful. Skin biopsy (surgically taking a small piece of skin using
local numbing medicine) may be useful in atypical or widespread cases.
What does keratosis pilaris look like under the microscope?
Microscopic
examination of the body tissue by a pathologist or dermatopathologist under high
magnification is called histopathology or pathology. Histopathology of KP shows
mild hyperkeratosis of the epidermis (thickening of the outer layer of skin),
hypergranulosis (increase in the special granular cells of the epidermis), and
plugging of individual hair follicles. The upper dermis (layer of the skin below
the epidermis) may have some microscopic inflammation called mild superficial
perivascular lymphocytic inflammatory changes.
Is keratosis pilaris curable?
There is no available cure, miracle pill, or
universally effective treatment for KP. It sometimes clears completely by itself
without treatment.
Is keratosis pilaris contagious?
KP is not contagious. It is not an infection
and is not caused by a fungus, bacterium, or virus. People do not give it to
someone else through skin contact and do not catch it from anyone else. Some
people are simply more prone to developing KP because of genetics and skin type.
What are possible complications of keratosis pilaris?
Complications are infrequent since it's primarily a cosmetic skin condition.
However, temporary skin discoloration called postinflammatory hypopigmentation
(lighter than the regular skin color) or hyperpigmentation
may occur after the inflamed, red bumps have improved or after a temporary
flare. Permanent scarring may rarely occur from deep picking, overly aggressive
treatments, or other inflammation.
Does diet have anything to do with keratosis pilaris?
Overall, diet does not
seem to affect KP. Vitamin A deficiency may cause symptoms similar to KP, but it's not a known cause of KP.
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