Bromhidrosis refers to an offensive or unpleasant body odor arising from apocrine or eccrine gland secretions.
Chronic disorder that most often develops in the axillae, but may also involve the genitals or plantar aspect of the feet.
The best-characterized short-chain fatty acid causing odor is ε-3-methyl-2-hexenoic acid.
Surgical removal of affected glands may be effective.
Body odor, osmidrosis, is a common phenomenon in a postpubertal population. Bromhidrosis refers to offensive body odor that is excessive or particularly unpleasant, which prominently arises from apocrine and eccrine glands. Bromhidrosis is most often reported in the axillae (apocrine bromhidrosis). This condition may contribute to impairment of an individual’s psychosocial functioning. The terminology in the literature is sometimes confusing, using osmidrosis to imply offensive odor, and bromhidrosis to imply osmidrosis in the setting of concomitant hyperhidrosis (excessive eccrine sweat gland secretion).1
Apocrine bromhidrosis usually occurs after puberty. It exhibits a male predominance, which may be a reflection of greater apocrine gland activity in men than in women. There is no seasonal or geographic predilection, although summer months or warm climates may aggravate the disease. Poor personal hygiene also may be a contributing factor. Bromhidrosis is usually an individual condition, whereas apocrine bromhidrosis has been reported in asian families.2
ETIOLOGY AND PATHOGENESIS
Apocrine secretion is predominantly responsible for odor production, primarily through bacterial action on its components.3 It is accepted that the odorous steroids, the so-called pheromones, among them 16-androstenes, 5α-androstenol, and 5α-androstenone, contribute to osmidrosis.4,5 5α-Reductase type I is expressed in apocrine glands. Individuals with osmidrosis have increased levels of 5α-reductase in their apocrine glands. Because this enzyme catalyzes the conversion of testosterone to 5α-dihydrotestosterone, levels of 5α-dihydrotestosterone may be greater than testosterone in the skin of affected individuals.6 The biotransformation of these steroids is complex and further research is required to delineate these pathways.
Moreover, the axilla hosts many different bacteria, most of which are Gram-positive. Bromhidrosis has been particularly associated with the action of aerobic Corynebacterium species.3 Axillary bacterial florae produce the distinctive axillary odor by transforming nonodoriferous precursors in sweat to ammonia and short-chain, malodorous, volatile fatty acids. The most common of these are ε-3-methyl-2-hexenoic acid and (RS)-3-hydroxy-3-methlyhexanoic acid, which are released through the action of a specific zinc-dependent N-alpha-acyl-glutamine aminoacylase from Corynebacterium species.6,7 ε-3-Methyl-2-hexenoic acid is delivered to the surface of the skin on 2 binding proteins, apocrine-secretion binding proteins 1 (ASOB1) and 2 (ASOB2). ASOB2 has been identified as apolipoprotein D.8
One study proposed an autosomal dominant inheritance pattern for apocrine bromhidrosis. Newer studies have found a strong relationship between bromhidrosis and wet ear wax associated with the single nucleotide polymorphism rs 17822931 of the ABCC11 gene.9,10
Eccrine secretions are distributed in a ...