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Alopecia mucinosa introduction
The inflammatory condition of the pilosebaceous unit (the hair
follicle and the sebaceous gland together) that can result in both
scarring as well as non-scarring alopecia is termed “alopecia
mucinosa”. The severity of the alopecia is dependant on the
degree of follicular destruction. The presence or absence of scarring
is indicative of the stage of this disease.
Also referred to as follicular mucinosis, alopecia mucinosa was
first reported by Dr. Herman Pinkus in 1957. Mucinoses are an assorted
group of uncommon skin disorders, which involve accumulation in
the skin of abnormal amounts of mucin. Mucins have the appearance
of being a stringy clear or whitish substance. They are mainly made
up of hyaluronic acid in the skin (a normal component of the connective
tissue in the dermis or middle layer of the skin). The diagnostic
hallmark of alopecia mucinosa, therefore, is the presence of depositions
of mucin around hair follicles as seen under the microscope.
The dermatologic eruptions consist of follicular papules with or
without hardened plaques. This indicates the presence of definite
changes in the hair follicles that lead to hair loss. The accumulation
of mucinous material in the damaged hair follicles and sebaceous
glands creates an inflammatory condition and leads to a subsequent
degenerative process. The face, the neck, and the scalp are the
most frequently affected sites, although lesions may appear on any
part of the body.
Some authors have documented two distinct types of alopecia mucinosa:
primary idiopathic alopecia mucinosa where the cause is unknown
and secondary lymphoma associated disease. Lymphoma is the name
given to a group of tumors that attack the lymphatic system of the
body. In some patients, these conditions appear to develop concomitantly;
and individuals exhibiting only alopecia mucinosa may be at risk
for subsequent development of lymphoma. Therefore, rather than define
them as two distinct types of hair loss, many consider primary and
secondary alopecia mucinosa to represent markers in the broader
spectrum of clinical presentations of the condition.
Similar to all other forms of scarring alopecia,
research and studies have not yet been able to pinpoint what exactly
causes
alopecia mucinosa,
but it may have links with circulating immune complexes and cell-mediated
immunity. Some experts claim that a T-cell (the type of lymphocyte
which is responsible for cell-mediated immunity) infiltrate stimulates
the production of mucin by the keratinocytes, triggering follicular
mucinosis. There is conjecture that S. aureus infection is also
a possible cause of alopecia mucinosa. What is clear is that mucinous
material deposits and accumulates in hair follicles and sebaceous
glands to create an inflammatory condition that subsequently breaks
down the ability of the affected follicles to produce hair.
Alopecia
mucinosa clinical
features
Alopecia mucinosa can be seen in any age group, with the reported
onset being as early as infancy. Lesional pruritis or intense itching,
dysethesia (burning or tingling sensation), and anhidrosis (the
inability to sweat in response to heat) are documented clinical
symptoms of alopecia mucinosa. Application of pressure on the diseased
sites or on the biopsy samples can squeeze out clear mucinous fluid
from the follicular ostia. The head and neck are parts of the body
most commonly involved, but disease can be widespread.
Early clinical signs of the disease are the occurrence of grouped
follicular papules similar to raised spots that appear in reddened
patches. They are typically 2-5 cm in diameter, but can be larger.
One or more lesions may be present from the start of the condition
or a single lesion may progress into multiple lesions as the disease
advances. These lesions are usually pink. Hair loss is common from
the affected follicles. In the early stages, hair loss is reversible
and the hair can grow back if the progress of the condition is successfully
arrested.
In more severe or advanced stages of disease, complete follicular
destruction prevents normal hair growth even if the skin disorder
is controlled. There may be finely scaled tumors, non-inflamed
patches and these eventually cause complete hair loss. A scleroderma
like
plaque or an erythematosus (reddened) crusted plaque associated
with S. Aureus infection has also been documented in alopecia
mucinosa.
There may be partial or complete hair loss in the affected area;
and the pull test may be positive. The hair pull test is a simple
test that gives a rough estimate of how much hair is being lost.
A dermatologist takes a few strands between their thumb and
forefinger and pulls on them gently. Anagen or growing hairs
should remain
rooted in place while hairs in telogen (when the follicle is
in a so-called resting state) state should come out easily.
By determining
how many hairs were pulled and the number that came out, dermatologists
roughly work out the percentage of hair follicles in a telogen
state.
Alopecia mucinosa can result in both scarring and non-scarring
alopecia, and in non-scarring cases, hair growth may be scanty for
months after disease remission. In adults, mycosis fungoides (MF)
is the most common malignancy associated with alopecia mucinosa.
Mycosis fungoides is a long-term, rapidly developing form of cutaneous
T-cell lymphoma or cancerous disease that affects the skin. Onset
of mycosis fungoides can precede, follow or occur simultaneously
with the manifestation of alopecia mucinosa. Malignant transformation
can occur over months to years. Hodgkin’s lymphoma is the
predominant malignancy observed in children and young adults, and
when present with alopecia mucinosa, the condition has poor therapeutic
prospects. Several other types of alopecia mucinosa associated malignancies
have also been reported.
Alopecia
mucinosa differential diagnosis
Scalp alopecia mucinosa can be confused with other forms of Mycosis
fungoides. This kind of alopecia also shares features with other
forms of alopecia like alopecia areata, lichen planopilaris and
lichen planus follicularis timidus, another, specific form of follicular
lichen planus.
The alopecia mucinosa condition, in which the hair shafts are
prone to breakage, displays similar black dots as seen in tinea
capitis,
a fungal disease of the scalp. Alopecia mucinosa must also be
distinguished from telogen effluvium, a form of nonscarring
alopecia characterized
by hair shedding and caused by a metabolic or hormonal stress
or by medications.
Morphea, a disorder characterized by thickening and indurations
of the skin (as well as of the subcutaneous tissue) due to excessive
collagen deposition also resembles alopecia mucinosa sometimes.
Lichen striatus, a rash that consists of small raised bumps
can mimic alopecia mucinosa but can be distinguished as it usually
does not cause any itching or other symptoms. Alopecia mucinosa
can be
differentiated from dissecting cellulites, a type of inflammation
affecting the scalp, as the latter is seen as yellowish pustules
over the scalp that leaves behind irregular scars on the scalp.
Alopecia
mucinosa pathology
As the clinical findings mimic other forms of alopecia, a skin
biopsy is necessary to clearly distinguish alopecia mucinosa from
conditions, which may look very similar.
Early disease is marked by a variable amount of mucin in follicular
epithelial interstices, easily perceived by the use of mucin counter-stains.
Biopsy reveals a perifollicular, follicular and perivascular lymphocytic
infiltrate. In general, the hair follicle and sebaceous glands show
mucin, which may coalesce to form small cysts. In cases associated
with lymphoma, the inflammatory infiltrate is deeper in the skin
and more intense. In addition, there is abnormality of the lymphocytes.
Follicular destruction is evident by a residual tract of mucin cuffed
by inflammatory cell-remains.
Similar to the clinical aspect of the condition, there are no definitive
or reliable histopathologic factors, which differentiate between,
benign and malignancy associated alopecia mucinosa. Certain manifestations,
when seen collectively, are suggestive, but do not decisively point
to lymphoma–related disease. In cases of doubt, multiple biopsies
may be required before a definitive diagnosis can be reached.
Alopecia
mucinosa treatment
Detailed case history, thorough physical examination, scalp biopsy
and correct interpretation of gathered information is necessary
prior to reaching diagnostic deductions and commencement of therapy.
In rare cases, primary alopecia mucinosa, which has occurred in
children, has cleared itself spontaneously. In case of chronic benign
alopecia mucinosa, an effective standard therapy is not defined.
Long term follow up with regular examinations including lymph node
palpation is essential in children and adults alike. As the disease
progresses, several biopsies may be required to check whether the
line of treatment has been bring about a favorable response or not.
Some therapeutic modalities that have been tried with varying degrees
of success include:
- Topical, intralesional and systemic corticosteroids
- Topical
and oral retinoids (a class of chemical compounds that are related
chemically to vitamin A), including Isotretinoin
- Oral Antibiotics
- Dapsone (antibiotic medication used in the treatment
of skin infections)
- Phototherapy (use of UV light in treatment)
- Superficial X ray
radiation (though this is rarely used today except perhaps as
a last resort)
- Excision or surgery
- In S. aureus culture positive alopecia mucinosa,
treatment with an oral anti staphylococcal agent can bring about
lesion clearance
Secondary Alopecia Mucinosa or cases associated with mycosis fungoides
merit malignancy related therapy, particularly if there is certainty
of cutaneous T-cell lymphoma.
It is important to note that any of these lines of treatment may
produce harmful side effects and hence the patients should be closely
monitored. It has been noticed in many instances that patients respond
to combination therapies. Once there is visible progress, it is
advisable to taper the drugs with undesirable side effects.
Alopecia
mucinosa references
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