Head Lice Infestation (Pediculosis Capitis) on Darker Skin

00:00 Welcome to a lecture on Pediculosis.

00:03 This is a condition where one gets infestation with lice.

00:09 Lice are ectoparasites that live on the human body.

00:14 They are wingless with six legs.

00:19 They have strong claws that are used to grasp onto hair shafts or clothing fibers.

00:26 They have piercing mouthparts are used to puncture the skin to feed on human blood.

00:34 Their injected saliva into the skin causes pruritus.

00:39 Right. So we've described the the lice.

00:42 Now we're going to discuss the types that infest humans.

00:47 The head lice. The first one is called the pediculus humanus capitis.

00:54 The second type, the body lice, is called pediculus humanus corporis.

01:00 And the third type is the pubic lice called pthirus pubis.

01:05 It's smaller, with short bodies resembling a crab, hence the common name crab lice.

01:12 So talking now about the head lice or pediculus humanus capitis, it affects all socio-economic groups and it's most prevalent among individuals aged 4 to 14 years. Some of the risk factors include female sex, a greater number of children in a family, and sharing of intimate objects.

01:39 This is, of course, still controversial.

01:43 The contribution of inanimate objects to the spread of pediculosis capitis is controversial. While a study performed in an experimental setting suggests that use of hair dryers, combs, or towels could lead to louse transmission, some other studies investigating the prevalence of lice lies on heads, bedding and floors after exposure to an infested individual have not supported these routes of transmission.

02:14 It can also be used to direct contact with the head of an infected person.

02:20 The lice do not jump or fly or use pets as vectors.

02:25 It is by contact. Here you can see a patient with lice on their hair, as well as the nits, which are the eggs of the louse.

02:41 Right here you see eggs or nits, and this is the white grain that is attached to the hair shaft. You sometimes have to use a microscope to see this or use a dermatoscope. Lice commonly infest the nape of the neck and the skin behind the ears.

03:01 The complications include dermatitis, secondary bacterial infection, for example, impetigo and one m ay also have tender, swollen lymph nodes. The diagnosis is usually clinical, and one has to identify the lice or nits on the scalp or any other area that is suspected. A lice comb can be used for removal and identification, but try not to use this for curly afro textured hair because it's too thin space and it will break the hair.

03:38 Trichoscopy can also be used to confirm a diagnosis of lice.

03:45 The differential diagnosis includes haircuts.

03:49 These are white to yellow tubular sheets that encircle the hair shafts, and these are normally seen sometimes in afro-textured hair due to mechanical pulling or tight braids. Piedra is a fungal infection which is most commonly found in tropical areas, and it can also be a differential of.

04:15 Pediculosis. Treatment involves the fact that the presence of living lice needs to be confirmed first.

04:29 Patients with nits, but without nymphs or adult lice are likely do not have an active infection and do not require treatment, please note that.

04:40 Topical treatment includes permethrin, which is applied for ten minutes to clean almost dry hair at a concentration of 1%.

04:51 You can also use 5% cream, which is applied for 8 to 12 hours.

04:57 Hair should be washed with water after the recommended time.

05:02 No shampoo to be used for 24 to 48 hours after treatment to ensure that the medication stays on the hair. Oral ivermectin can be used in cases of refractory infestation at a dose of 200mg/kg, and this may need to be repeated after 7 to 10 days if live lice are still visible.