Telogen Effluvium following Dengue Fever

I saw a case of female hair loss yesterday. A young lady aged 24 years who complaind of increased shedding of hair over 1 month. Firstly you should exclude thyrotoxicosis and other obvious causes like trichotillomania. However in Tellogen Effluvium there is usually a period of stress up to 6 months before. In this case, she had just recovered from dengue fever. Emedicine has a good article here. These are the salient points.

Background: Telogen effluvium is a form of nonscarring alopecia characterized by diffuse hair shedding, often with an acute onset. A chronic form with a more insidious onset and a longer duration also exists. Telogen effluvium is a reactive process caused by a metabolic or hormonal stress or by medications. Generally, recovery is spontaneous and occurs within 6 months.

Pathophysiology: Telogen effluvium can affect hair on all parts of the body, but, generally, only loss of scalp hair is symptomatic.

Understanding the pathophysiology of telogen effluvium requires knowledge of the hair growth cycle. All hair has a growth phase, termed anagen, and a resting phase, telogen. On the scalp, anagen lasts approximately 3 years, while telogen lasts roughly 3 months, although there can be wide variation in these times between individuals. During telogen, the resting hair remains in the follicle until it is pushed out by growth of a new anagen hair.

In most people, 5-15% of the hair on the scalp is in telogen at any given time. Telogen effluvium is triggered when a physiologic stress or hormonal change causes a large number of hairs to enter telogen at one time. Shedding does not occur until the new anagen hairs begin to grow. The emerging hairs help to force the resting hairs out of the follicle. Recent evidence suggests that the mechanism of shedding of a telogen hair is an active process that may occur independent of the emerging anagen hair. The interval between the inciting event in telogen effluvium and the onset of shedding corresponds to the length of the telogen phase, between 1 and 6 months (average 3 mo).

Causes: Physiologic stress is the cause of telogen effluvium. These inciting factors can be organized into several categories, noted below. Evidence from mouse studies indicates that psychological stress can induce catagen, mainly by effects on neurotransmitters and hormones. In humans, however, the role these effects play in hair loss has not yet been determined. In HIV disease, apoptosis may be related to HIV-1 viral protein R.

• Acute illness such as febrile illness, severe infection, major surgery and severe trauma

• Chronic illness such as malignancy, particularly lymphoproliferative malignancy; and any chronic debilitating illness, such as systemic lupus erythematosus, end-stage renal disease, or liver disease

• Hormonal changes such as pregnancy and delivery (can affect both mother and child), hypothyroidism, and discontinuation of estrogen-containing medications

• Changes in diet like crash dieting, anorexia, low protein intake, and chronic iron deficiency

• Heavy metals such as selenium, arsenic, and thallium

• Medications, of which the most frequency cited are beta-blockers, anticoagulants, retinoids (including excess vitamin A), propylthiouracil (induces hypothyroidism), carbamazepine, and immunizations

• Allergic contact dermatitis of the scalp

Because acute telogen effluvium is a reactive process, which resolves spontaneously, treatment usually is limited to reassurance.

While topical minoxidil is not proven to promote recovery of hair in telogen effluvium, this medication has a theoretical benefit and is well tolerated. Patients who are eager to play an active role in their treatment may choose to use minoxidil.