dermatology question

Lichen nitidus would indicate keratosis pilaris.

Other than that your description is too vague. Perhaps if you provide a picture or some more information about the patient (e.g., age, history, etc.), the diagnosis _may_be_ more discernible.

 

They actuall taught that at MIT?

 

hey mycin...r u speaking in greek?? Ive never heard of those terms... ive heard of lichen planus and actinic keratosis


The skin condition sounds like folliculitis, if u r reffering to pustules.

agrees w/ mycin...a better description, onset, picture, would be good

 

No. Only 2.6% of what I said was [in] Greek. Lichen is Greek; nitidus, keratosis, and pilaris are Latin. The rest is English, or Latin-derived abbreviations.

 

it's keratosis pilaras. just tell them to use a non-perfumed soap and to moisturize it really well. it's a very common skin problem and isn't a big deal.

take it easy

homonculus

 

Lichen nitidus and keratosis pilaris are two unrelated conditions, though they may be similar in appearance -- not sure what you mean by one indicating the other.

 

I was simply taking him through my thought process to balance for the brevity of his presentation. Lichen nitidus is a differential diagnosis for keratosis pilaris. Keratosis pilaris is _basically_ (there are slight visual aberrancies as well) non-koebnerizing lichen nitidus.

Had there been any trauma or previous injury to this patient's upper arm, I am _sure_ the original poster would have mentioned it. Thus, I assumed there was no koebnerization. Non-koebnerized lichen nitidus would indicate keratosis pilaris.

 

possibly mild psoriasis? (he says he's had it for as long as he can remember)

 

Let's define a few terms here, for the sake of illuminating readers of this thread.

Keratosis pilaris: an extremely common ckin condition, often hereditary, that manifests itself as tiny papules over hair follicles, kind of like hard goosebumps; it's caused by the follicles' getting plugged up by excess keratin. The bumps are white to rosy, and the most common site is the outer upper arms; thighs are a popular location as well.

Lichen nitidus: a relatively rare skin condition of unknown cause that consists of groups of shiny, flat-topped skin-coloured papules. Most common locations: trunk/abdomen, forearms, buttocks, genitalia. May exhibit Koebner phenomenon.

Koebner phenomenon: the tendency of a lesion to appear at the site of an injury such as a scratch. Leads to a linear distribution pattern. Characteristic of certain skin conditions such as psoriasis, warts, and lichen niditus.

 

You outlined the primary visual differences between keratosis pilaris and lichen nitidus:

(1) Lichen nitidus presents with flatter papules
(2) The nitidus, or shiny appearance of the papules
(3) The linear arrangement of papules in lichen nitidus due to the Koebner phenomenon

We know nothing of the third with regards to this particular patient. And a skin-colored, _comparatively_ flat and shiny papule could easily be mistaken for an inflamed white bump (maybe moreso in a caucasian, which we also know nothing about).

And of course, there's the non-visual anomaly, the prevalence of keratosis pilaris when compared to lichen nitidus.

I'm a stickler for not eliminating rare conditions, especially when we know so little about something. We indeed know very little about this patient. We neither know the gender nor the age of this patient (cf., "who said _she's_ had them as long as _he_ can remember"). Incidentally, keratosis pilaris primarily affects adolescent females. Thus, it's _way_ too premature to make any conclusions based on statistics (e.g., the rarity of a condition). Furthermore, it doesn't even look like the original author is coming back to check for responses.

Who knows, maybe it is lichen nitidus, maybe it's keratosis pilaris, or maybe it's something altogether different. The point is, we have way too little information to make any sort of reasonable diagnosis.

 

Oh, agreed. "small white bumps and redness" could be anything. I just think it's fun to debate possibilities.

You don't necessarily get a linear distribution of papules (i.e., Koebner phenomenon) in lichen nitidus, though if you do see this you'd rule out keratosis pilaris.

 

Goodness!

A description of "white bumps and redness" is far too vague.

Jumping to diagnoses strikes me as a bit silly without knowing more about the patient's history and associated symptoms.

For all anyone knows, this could be an immunocompromised patient, thereby broadening any differential. Further, we don't know if the lesion is pruritic. We don't know about its' true distribution (bilateral upper arms -- sun exposed?). Has the patient tried any over the counter lotions? Anything make the lesion better or worse? Are these papules? Vesicles? Pustules? Are they crusted? How old is the patient? Is this a child? What is the patient's gender (unclear from the original post)? How has the lesion changed over time?

For all we know, this could be nearly any dermatologic condition. The information provided is hardly sufficient for arguing over something as esoteric as lichen nitidus.

Cheers,
doepug

 

This would be true if we attempting to generate an accurate differential for the patient. But I don't think any lack of patient-specific information precludes one from having a theoretical discussion of obscure skin conditions. And I think most posters in this thread are plenty aware that we're necessarily operating in the realm of theory here. Look at the two posts immediately prior to your own.