Everything about Favus totally explained
Favus (Latin for "honeycomb") is a
disease of the
scalp, but occurring occasionally on any part of the skin, and even at times on
mucous membranes. The uncomplicated appearance is that of a number of yellowish, circular, cup-shaped crusts (
scutula) grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair projecting in the center. These increase in size and become crusted over, so that the characteristic
lesion can only be seen round the edge of the
scab. Growth continues to take place for several months, when scab and
scutulum come away, leaving a shining bare patch destitute of hair. The disease is essentially chronic, lasting from ten to twenty years. It is caused by the growth of a
fungus, and pathologically is the reaction of the tissues to the growth. It was the first disease in which a fungus was discovered by
J. L. Schönlein in
1839; the discovery was published in a brief note of twenty lines in Millers Archive for that year (p. 82), the fungus having been subsequently named by
Robert Remak;
Achorion schoenleinii after its discoverer. The fungus was named after a microscopic structure termed "achorion" (a term not used in modern science), seen in scrapings of infected skin, which consists of slender,
mycelial threads matted together, bearing oval, nucleated fungal substrate-
arthroconidia either free or jointed. This structure is currently called "scutula." The fungus itself is now called
Trichophyton schoenleinii.
During initial infection, the fungal spores would appear to enter through the unbroken cutaneous surface, and to germinate mostly in and around the
hair follicle and sometimes in the shaft of the hair. In
1892, two additional "species" of the fungus were described by
Paul Gerson Unna, the
Favus griseus, giving rise to greyish-yellow scutula, and the
Favus sulphureus celerior, causing sulfur-yellow scutula of a rapid growth. This was in the days before scientists learned to rigorously distinguish microorganism identities from disease identities, and these antique, ambiguous disease-based names no longer have status either in
mycology or in
dermatology.
Up until the advent of modern therapies, favus was widespread worldwide; prior to Schönlein's recognition of it as a fungal disease, it was frequently confused with
Hansen's disease, better known as
leprosy, and European sufferers were sometimes committed to leprosaria. Today, due to this species' high susceptibility to the antifungal drug
griseofulvin, it has been eliminated from most parts of the world except rural central Asia and scattered rural areas of Africa. It is mainly a disease connected to demographic poverty and isolation, but is so readily treatable that it's among the diseases most likely to be completely eliminated by modern medicine.
Similar looking infections, sometimes diagnosed as favus but more often as atypical inflammatory tinea, may rarely be produced by agents of more common dermatophyte fungal infections, in particular
Microsporum gypseum, the most common soil-borne dermatophyte fungus, and
Trichophyton mentagrophytes (name used in post-
1999 sense for a
phylogenetic species formerly referred to as
Trichophyton mentagrophytes var.
quinckeanum), the agent of favus infection of the mouse.
Further Information
Get more info on 'Favus'.
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