|
Infectious
hair disease
Several types of lice, bacteria, and fungi can invade the scalp
and cause numerous problems. These infectious agents of the
scalp
and other regions of hair are collectively called "dermatophytes".
Different dermatophytes are common in different parts of the
world
and at different times in history. The same clinical diagnosis
today may be caused by something very different than the same
clinical diagnosis fifty years ago. For example the most common
cause of tinea capitis in Europe and the USA in 1955 was Microsporum
audouini. Today the most common cause of tinea capitis may be
due to other infectious agents such as Trichophyton tonsurans
and
Microsporum
canis in Europe.
Scalp infections and infestations are still very
common today, even in the developed Western world.
Because the diseases are
due
to bacteria, fungi, viruses, and microscopic animals, they can
easily be transmitted from one individual to another. Transmission
usually
occurs between those living in close proximity to each other where
there may be physical contact. However, it is also possible to
transmit
infectious scalp agents through using contaminated towels, from
contact with infected animals including pets, or even from contact
with contaminated soil or water. “Hot Tub” Folliculitis
is a condition caused by the pathogen Pseudomonas
Aeruginosa, and is often seen
where spa and public bath sanitation is at fault. Public hot tubs
are a particularly common source of infection, as they are nice
and warm, but often not very clean, so the bacteria
can survive and
as so many people use them cross infection is easy.
Infectious diseases of the hair follicle may be caused by bacteria,
fungi, viruses or parasites, but the most common skin pathogens
that cause infectious skin and hair diseases are bacteria or fungi.
In bacterial infections, Staphylococcus aureus and
a group of bacteria called Hemolytic
Streptococci are particularly common. The pathogens identified
in Gram-negative folliculitis include Klebsiella, Enterobacter,
and
Proteus species. The type of fungus in fungal infections varies
signficantly.
Viral infections of hair follicles are relatively rare and where
it does occur it is almost always caused by Herpes Simplex. Mites
such as Demodex folliculorum and Demodex brevis are natural and
common parasites of the human pilo-sebaceous follicle. Usually
they live a benign life and promote nothing more than a mild itch
(if you have itchy eyelids it is most likely a Demodex infestation
that is causing it). However, occasionally Demodex species can
sometimes induce a stronger inflammatory reaction and folliculitis
is the result. A yeast induced folliculitis is quite rare, but
Pityrosporum folliculitis is caused by pityrosporum yeasts and
very rarely Candida albicans can
cause folliculitis in immunocompromised individuals.
Because there can be such a wide variety of infectious pathogens
that can cause folliculitis or worse, a careful evaluation of
the condition is important to ensure the most appropriate treatment
is provided.
This section of the web site examines different forms of hair
follicle infection or skin infection that can affect adjacent
hair follicles.
Infectious
hair disease references
- Roberts BJ, Friedlander SF. Tinea
capitis: a treatment update. Pediatr Ann. 2005 Mar;34(3):191-200.
PMID: 15792111
- Kyle AA, Dahl MV. Topical therapy
for fungal infections. Am J Clin Dermatol. 2004;5(6):443-51.
PMID: 15663341
- Luelmo-Aguilar J, Santandreu MS.
Folliculitis: recognition and management. Am J Clin Dermatol.
2004;5(5):301-10. PMID: 15554731
- Gupta AK, Batra R, Bluhm R, Boekhout T, Dawson TL Jr. Skin
diseases associated with Malassezia species. J Am Acad Dermatol.
2004 Nov;51(5):785-98. PMID: 15523360
- Guay DR. Treatment of bacterial
skin and skin structure infections. Expert Opin Pharmacother.
2003 Aug;4(8):1259-75. PMID: 12877635
- Hainer BL. Dermatophyte infections.
Am Fam Physician. 2003 Jan 1;67(1):101-8. PMID: 12537173
- Stulberg DL, Penrod MA, Blatny RA. Common bacterial skin
infections. Am Fam Physician. 2002 Jul 1;66(1):119-24. PMID:
12126026
- Mengesha YM, Bennett ML. Pustular
skin disorders: diagnosis and treatment. Am J Clin Dermatol.
2002;3(6):389-400. PMID: 12113648
- Gupta AK, Summerbell RC. Tinea capitis.
Med Mycol. 2000 Aug;38(4):255-87. Review.
PMID: 10975696
- Weitzman I, Summerbell RC. The dermatophytes.
Clin Microbiol Rev. 1995 Apr;8(2):240-59.
PMID: 7621400
|
