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Favus in Adult
See also in: Hair and Scalp
Other Resources UpToDate PubMed

Favus in Adult

See also in: Hair and Scalp
Contributors: Laurie Good MD, Whitney A. High MD, JD, MEng, Susan Burgin MD
Other Resources UpToDate PubMed

Synopsis

Favus (tinea favosa), a Latin word meaning honeycomb, is a severe form of tinea capitis caused most often by Trichophyton schoenleinii. Occasionally, Trichophyton violaceum or Microsporum species may cause a similar condition.

While favus used to occur worldwide, vast improvements in socioeconomic conditions have limited it to areas where the population suffers from poor hygiene and malnutrition. Currently, favus is mostly seen in Africa, some parts of Asia and the Middle East, and some parts of Eastern Europe; it is rarely encountered in the United States or Western Europe. Typically, scalp favus is acquired during childhood through close contact with other affected individuals. Combs and hairbrushes remain an important source of infection.

Scalp favus presents first as erythematous papules surrounding intact hair follicles. The papules become more inflamed and eventually develop characteristic thick, yellow-brown crusts composed of hyphae and keratin debris, resembling a honeycomb. T schoenleinii is an endothrix (residing within the hair shaft), and it destroys the hair shaft, eventuating in hair loss. Left untreated, concave, cup-shaped debris (termed scutula) steadily engulf ever more hair, leading to a progressive scarring alopecia.

Favus of scrotal skin is a rarely reported variant of favus. Most cases of scrotal favus are due to Nannizzia gypsea (previously known as Microsporum gypseum) and Trichophyton rubrum. Thick, cup-shaped, white scales are seen on the scrotum. In one study, most patients with scrotal favus had concomitant tinea pedis. Scrotal favus is predominantly seen in adulthood, but teenagers with the disease have been reported. A minority of the reported patients with scrotal favus had known human immunodeficiency virus (HIV) infection.

Codes

ICD10CM:
B35.9 – Dermatophytosis, unspecified

SNOMEDCT:
85375000 – Tinea favosa

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Differential Diagnosis & Pitfalls

The differential diagnosis of scalp favus is similar to that for tinea capitis. Other entities to consider in the differential diagnosis include:
  • Seborrheic dermatitis – Not typically seen in children before puberty, as they lack the appropriate cytokine milieu to develop this condition.
  • Psoriasis – Not common in children, in whom favus is most pervasive; psoriasis also tends to involve preferentially the occipital scalp and/or have other skin or nail involvement to suggest the disease.
  • Atopic dermatitis – A pervasive disorder that in school-aged children typically also involves the flexural areas of the body, such as the antecubital and popliteal areas.
  • Lichen planopilaris – An unusual condition and cause of scarring alopecia, often associated with lichen planus on other areas of the skin or mucosa.
  • Discoid lupus erythematosus – An extremely unusual condition in children, it also involves other areas of the head and neck, such as the conchal bowls, and is associated with sun sensitivity.
  • Folliculitis decalvans – A form of purulent scarring alopecia that is unusual in children of the age typically affected by favus.
  • Central centrifugal cicatricial alopecia – A form of scarring alopecia most common in middle-aged women, usually in those individuals with an extensive history of chemical or thermal straightening of the hair.
Additionally, scutula can create an environment well suited for secondary bacterial infection, which may confound culture results taken from the surface.

Differential diagnosis of scrotal favus:

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Therapy

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References

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Last Reviewed:08/15/2019
Last Updated:09/08/2019
Copyright © 2021 VisualDx®. All rights reserved.
Favus in Adult
See also in: Hair and Scalp
Favus : Scalp, White scaly plaque, Focal scarring alopecia
Clinical image of Favus
Copyright © 2021 VisualDx®. All rights reserved.