Simple cases
Case 17
17
History
What is troubling you?
My scalp, back of the neck and especially behind the ears have been itchy for about a week.
It is wise to start with a neutral question. Here is it very helpful, as this dermatosis favors the nape and retroauricular regions.
Does anyone else in the family have similar problems?
No, but my little brother has a few red spots on his neck. The girl I sit next to in school is always scratching her head.
This disorder is transmitted by direct contact. It is most common in children and often epidemics are seen in kindergartens and schools.
Have you ever had an itchy scalp before?
No, never.
Good question to exclude chronic scalp dermatoses such as psoriasis and seborrheic dermatitis.
Are you itching anywhere else?
No.
Good question to exclude other causes of more generalized pruritus, such as scabies. Total body inspection important.
Have you tried a new shampoo recently?
I think my mom bought a new bottle.
This question is directed towards a possible allergic contact dermatitis, which can usually be excluded on clinical examination.
How often have you used the new shampoo?
Once; 2 days ago.
The history excludes this new shampoo, as the itching was present first.
Lesion
Choose the right efflorescences:
Correct. No distinct lesion is seen. The main complaint is pruritus and the main finding nits attached to some hairs on the posterior scalp.
Scales, as seen in psoriasis and seborrheic dermatitis, are not present here. Scales can be easily removed from the hair shaft, while nits are firmly attached.
Crusts sometimes occur with this disease following scratching and bleeding, but they are not seen today.
Diagnostika
Choose the right diagnosis:
Atopic dermatitis is a common cause of scalp pruritus in children, but other sites should be involved and the history more chronic.
Important differential diagnostic consideration. Seborrheic dermatitis does not have nits, usually also affects anterior scalp and is more chronic.
False. Scabies only involves the scalp in infants. In older children, it usually affects the interdigital spaces, nipples, penis and umbilicus.
Correct. The nits are diagnostic, but the history of itching on the nape ands behind the ears, as well as a classmate with similar itching, is highly suggestive.
Therapy
Choose the right therapy(ies):
This is for seborrheic dermatitis, not for lice.
Good. This is the standard treatment. In smaller children, wash off after 3 hours. Both lice and nits are killed.
A fine comb helps remove the nits, once they have been killed by lindane or an alternative agent such as permethrin or malathion.
Sometimes used in severe cases, but usually can be avoided.
