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Folliculitis decalvans
introduction
The term cicatricial alopecia encompasses a diverse group of disorders
characterized by permanent destruction of the hair follicle and
irreversible hair loss. A great deal of progress has been made in
understanding these diseases, but there is much more to be discovered
about the etiology, salient clinical features and therapeutic management
of the insidious scarring alopecia in its various forms.
Classification of the different types of scarring alopecia has
been done on the basis of various criteria and serves as a diagnostic
framework or guide to clinicians, pathologists and dermatologists.
The flip side to diagnosing scarring alopecia is that very often
the clinical and histological features overlap, making a definitive
diagnosis difficult to reach. The classification of alopecias as
categorized by the North American Hair Research Society is based
on the type of inflammatory cells that destroy the hair follicle
during the active stage of the disease. The inflammation may predominantly
involve lymphocytes or neutrophils, and therefore primary cicatricial
alopecias as classified by NAHRS are “lymphocytic” or “neutrophilic”.
Folliculitis decalvans comes under the category of neutrophilic
cicatricial alopecias. This is a commonly found primary scarring
alopecia, with an incidence rate of 1.9-11.2% in those diagnosed
with any form of scarring alopecia. The condition is typified by
a destructive, suppurative folliculitis, meaning inflammation of
the hair follicle with the presence of pus.
Folliculitis decalvans has been described as a cicatrical alopecia
characterized by erythematous scalp with pustules around the hair
follicles, commonly called Folliculitis. Each crop of pustules results
in progression of hair loss. Follicle destruction and scarring with
permanent hair loss is the end-result of the condition. The disease,
which affects both men and women, is almost inexorable and the condition
is well known for its resistance to treatment. Most often, the crown
is the affected area; in rare cases, however, the condition can
affect the beard, face and nape of the neck.
The onset of folliculitis decalvans can occur at any time after
adolescence. Young and middle aged adults of both sexes can be affected
by the disease. The condition progresses slowly and disease activity
waxes and wanes periodically. In most cases, a bacterium called
Staphylococcus Aureus can be isolated from the pustules, though
it is not clear how important this bacteria is for the development
of the scarring alopecia. The etiology of this form of scarring
alopecia is still undefined. Although the role of the bacteria as
a cause of the disease is unproven, an abnormal host response to
S. Aureus has been implicated by many authors. A genetically determined
immune deficiency with increased risk of follicular infection is
another possibility supported by case studies. Both acquired and
inherited immune disturbances are associated with folliculitis decalvans.
One school of thought considers folliculitis decalvans as a subset
of Central Centrifugal Cicatricial Alopecia (CCCA). These authors
purport that the pustules seen in folliculitis decalvans are a manifestation
of either bacterial superinfection, (the process by which a cell
that has previously been infected by one virus gets co-infected
with another virus at a later point in time), or an intense immune
response to degenerating follicular components. According to their
studies, if inflamed but non-pustular areas of affected individuals
are sent for biopsy, the histological findings are similar to those
seen in Follicular Degeneration syndrome or pseudopelade. They further
go on to state that if a pustule is sampled for biopsy, disintegration
of the upper half of the follicular epithelium and acute inflammation
will be observed. As it broadly overlaps with pseudopelade and Follicular
Degeneration syndrome, these authors believe that folliculitis decalvans
represents the same basic pathological process.
Folliculitis decalvans
clinical features
The initial lesion is seen as a pinpoint, reddened follicular pustule
or papule that is painful and full of pus. Yellowish pustules surrounding
the hair follicles develop over the top of the scalp and evolve
into miliary abscesses or lesions, the size of millet seeds. As
the disease progresses, the crops of pustules coalesce into wider
areas of folliculitis and hair loss.
Characteristically, these pustules crust and sometimes several
hair strands grow up out of a single follicle, so the scalp looks "tufted" like
a toothbrush. This is also known as “corn stalking”.
The process eventually leads to hair loss as the follicle is completely
destroyed and leaves behind a scar. The scars are irregular in shape
and are typically smooth, hairless, atrophic, flesh-colored or ivory-white
patches. Pinpoints of redness may temporarily mark the position
of former hair follicles. Due to severe scarring, permanent hair
loss occurs in the involved sites, and appears as a specifically
bordered zone of folliculitis.
There have been reports of associated extremity (arms and legs),
axillary (under arm) and pubic area involvement, but this may represent
coincident or alternative diagnosis. Although some authors consider
tufted hair folliculitis a feature of folliculitis decalvans, most
authorities are of the opinion that it is a different diagnosis
and a non-specific form of cicatricial alopecia.
Folliculitis decalvans
differential diagnosis
Diagnosis of the condition is based on clinical, microbiological,
histo-pathological and laboratory features. Folliculitis decalvans
can mimic classic folliculitis, acne necrotica, lichen planopilaris,
discoid lupus erythematosus, and dissecting cellulitis (also called
perifolliculitis capitis abscedens et suffodiens).
Grouped follicular pustules as seen in folliculitis decalvans are
not seen in ordinary folliculitis or acne necrotica. Dissecting
cellulitis can be distinguished easily as early pustules and papule
formation develop immediately into dermal nodules. In addition,
folliculitis decalvans does not display the sinus tract formation
in histological skin biopsies, a characteristic typical of dissecting
folliculitis.
Folliculitis decalvans shares features with acne keloidalis. Some
patients with acne keloidalis develop only follicular papules on
the nape of the neck, whereas others have been reported to develop
a progressive cicatricial alopecia that resembles folliculitis decalvans.
Folliculitis decalvans
pathology
Scalp biopsies are critical for the assessment and diagnosis of
scarring alopecia and are often employed when identifying folliculitis
decalvans. The histology of early lesions of folliculitis decalvans
shows prominent keratin plugging of the follicular infundibulum
(the segment of the hair follicle that extends from the entrance
of the sebaceous gland duct to the follicular orifice). When the
engorged follicle ruptures, an associated interstitial and perifollicular
inflammatory infiltrate is observed. Occasional dermal abscesses
may also be present, though significantly fewer than those seen
in dissecting cellulitis.
As the disease progresses, the infiltrate gets mixed with neutrophils,
lymphocytes, and plasma cells. Gradually the infiltrate extends
into the adventitial dermis. Granulomatous (nodular) inflammation
is typically observed in the mid and deep dermis. Lesions of advanced
stage disease show follicular and adventitial dermal fibrosis or
undesired development of excess fibrous tissue.
Use of special stains and cultures show presence of infectious
agents, the most common being S. Aureus. Sinus tract formation (abnormal
extensive tunnels) is absent.
Folliculitis decalvans
treatment
Until quite recently, folliculitis decalvans was a difficult condition
to treat, and prognosis of patients afflicted with this form of
alopecia was also rather bleak. As a rule, intact pustules should
be cultured, and sensitivity to various antibiotics should be determined.
The following has been documented:
- The condition can be controlled temporarily to some degree
by administering anti-staphylococcal antibiotics such as erythromycin,
cephalosporins, trimethroprim/ sulfamethoxozole, clindamycin,
or a fluoroquinalone with or without rifampin. Additionally, anti-nuetrophilic
and broad-spectrum antibiotics have been found to be variably
and
temporarily effective. However, early withdrawal of the drugs
has been seen to cause a relapse of the condition.
- In some severe
presentations, addition of an oral corticosteroid
has been effective. The addition of prednisone can improve efficacy,
but prednisone as a cortico-steroid has its own set of undesirable
side effects with long-term usage.
- Most authors advise the use
of topical antibacterial agents for eradication of S. Aureus.
- The limited data available on the efficacy of isotretinoin,
a retinoid, suggests that it is ineffective in treating folliculitis
decalvans.
- Rifampin, a bacteriocidal drug, with the combined use
of fusidic acid and zinc has led to successful remission lasting
from
months to years in some patients under study. It is important
to remember that Rifampin should never be used alone. The exact
scientific
base of the use of zinc is not established, but in all probability,
it has an anti-inflammatory effect and can modulate the immune
response. Rifampin and fusidic acid are probably effective because
of their
excellent intracellular penetration and pathogen eradication potential.
- Rifampin
in combination with clindamycin (an antibiotic) has also shown
positive responses.
All the above forms of treatment have their own side effects, and
benefits of treatment must be evaluated against the consequences
of the drugs. Rifampin causes red staining of bodily secretions
including tears. Zinc at high dosage levels competes with copper
metabolism and can result in severe refractory anemia and neutropenia,
a hematological disorder. The use of Clindamycin is associated with
a potential risk of colitis. Treatment with these drugs is only
merited when the benefits are seen to outweigh the side effects.
It is, therefore, the responsibility of the dermatologist or clinician
administering the therapy to ensure that close monitoring of the
patient is undertaken, and prolonged usage of these drugs is not
advisable.
Folliculitis decalvans
references
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